diff --git a/tests/fixtures/billing_request_templates.json b/tests/fixtures/billing_request_templates.json
index acc182eb..3b804705 100644
--- a/tests/fixtures/billing_request_templates.json
+++ b/tests/fixtures/billing_request_templates.json
@@ -5,24 +5,24 @@
     "method": "GET",
     "path_template": "/billing_request_templates",
     "url_params": [],
-    "body": {"billing_request_templates":[{"authorisation_url":"https://pay.gocardless.com/BRT123","created_at":"2021-01-01T12:00:00.000Z","id":"BRT123","mandate_request_constraints":{"end_date":"example end_date 101","max_amount_per_payment":101,"payment_method":"example payment_method 101","periodic_limits":[{"alignment":"creation_date","max_payments":101,"max_total_amount":101,"period":"week"}],"start_date":"example start_date 101"},"mandate_request_currency":"GBP","mandate_request_description":"Top-up Payment","mandate_request_metadata":{},"mandate_request_scheme":"bacs","mandate_request_verify":null,"metadata":{},"name":"12 Month Gold Plan","payment_request_amount":"100.00","payment_request_currency":"GBP","payment_request_description":"Top-up Payment","payment_request_metadata":{},"payment_request_scheme":"faster_payments","redirect_uri":"https://my-website.com/abc/callback","updated_at":"2021-01-01T12:00:00.000Z"},{"authorisation_url":"https://pay.gocardless.com/BRT123","created_at":"2021-01-01T12:00:00.000Z","id":"BRT123","mandate_request_constraints":{"end_date":"example end_date 102","max_amount_per_payment":102,"payment_method":"example payment_method 102","periodic_limits":[{"alignment":"calendar","max_payments":102,"max_total_amount":102,"period":"month"}],"start_date":"example start_date 102"},"mandate_request_currency":"GBP","mandate_request_description":"Top-up Payment","mandate_request_metadata":{},"mandate_request_scheme":"bacs","mandate_request_verify":null,"metadata":{},"name":"12 Month Gold Plan","payment_request_amount":"100.00","payment_request_currency":"GBP","payment_request_description":"Top-up Payment","payment_request_metadata":{},"payment_request_scheme":"faster_payments","redirect_uri":"https://my-website.com/abc/callback","updated_at":"2021-01-01T12:00:00.000Z"}],"meta":{"cursors":{"after":"example after 101","before":"example before 101"},"limit":50}}
+    "body": {"billing_request_templates":[{"authorisation_url":"https://pay.gocardless.com/BRT123","created_at":"2021-01-01T12:00:00.000Z","id":"BRT123","mandate_request_constraints":{"end_date":"example end_date 101","max_amount_per_payment":101,"payment_method":"example payment_method 101","periodic_limits":[{"alignment":"creation_date","max_payments":101,"max_total_amount":101,"period":"week"}],"start_date":"example start_date 101"},"mandate_request_currency":"example mandate_request_currency 101","mandate_request_description":"Top-up Payment","mandate_request_metadata":{},"mandate_request_scheme":"bacs","mandate_request_verify":"example mandate_request_verify 101","metadata":{},"name":"12 Month Gold Plan","payment_request_amount":"100.00","payment_request_currency":"example payment_request_currency 101","payment_request_description":"Top-up Payment","payment_request_metadata":{},"payment_request_scheme":"faster_payments","redirect_uri":"https://my-website.com/abc/callback","updated_at":"2021-01-01T12:00:00.000Z"},{"authorisation_url":"https://pay.gocardless.com/BRT123","created_at":"2021-01-01T12:00:00.000Z","id":"BRT123","mandate_request_constraints":{"end_date":"example end_date 102","max_amount_per_payment":102,"payment_method":"example payment_method 102","periodic_limits":[{"alignment":"calendar","max_payments":102,"max_total_amount":102,"period":"month"}],"start_date":"example start_date 102"},"mandate_request_currency":"example mandate_request_currency 102","mandate_request_description":"Top-up Payment","mandate_request_metadata":{},"mandate_request_scheme":"bacs","mandate_request_verify":"example mandate_request_verify 102","metadata":{},"name":"12 Month Gold Plan","payment_request_amount":"100.00","payment_request_currency":"example payment_request_currency 102","payment_request_description":"Top-up Payment","payment_request_metadata":{},"payment_request_scheme":"faster_payments","redirect_uri":"https://my-website.com/abc/callback","updated_at":"2021-01-01T12:00:00.000Z"}],"meta":{"cursors":{"after":"example after 101","before":"example before 101"},"limit":50}}
   },
   "get": {
     "method": "GET",
     "path_template": "/billing_request_templates/:identity",
     "url_params": ["BRT123"],
-    "body": {"billing_request_templates":{"authorisation_url":"https://pay.gocardless.com/BRT123","created_at":"2021-01-01T12:00:00.000Z","id":"BRT123","mandate_request_constraints":{"end_date":"example end_date 103","max_amount_per_payment":103,"payment_method":"example payment_method 103","periodic_limits":[{"alignment":"creation_date","max_payments":103,"max_total_amount":103,"period":"year"}],"start_date":"example start_date 103"},"mandate_request_currency":"GBP","mandate_request_description":"Top-up Payment","mandate_request_metadata":{},"mandate_request_scheme":"bacs","mandate_request_verify":null,"metadata":{},"name":"12 Month Gold Plan","payment_request_amount":"100.00","payment_request_currency":"GBP","payment_request_description":"Top-up Payment","payment_request_metadata":{},"payment_request_scheme":"faster_payments","redirect_uri":"https://my-website.com/abc/callback","updated_at":"2021-01-01T12:00:00.000Z"}}
+    "body": {"billing_request_templates":{"authorisation_url":"https://pay.gocardless.com/BRT123","created_at":"2021-01-01T12:00:00.000Z","id":"BRT123","mandate_request_constraints":{"end_date":"example end_date 103","max_amount_per_payment":103,"payment_method":"example payment_method 103","periodic_limits":[{"alignment":"creation_date","max_payments":103,"max_total_amount":103,"period":"year"}],"start_date":"example start_date 103"},"mandate_request_currency":"example mandate_request_currency 103","mandate_request_description":"Top-up Payment","mandate_request_metadata":{},"mandate_request_scheme":"bacs","mandate_request_verify":"example mandate_request_verify 103","metadata":{},"name":"12 Month Gold Plan","payment_request_amount":"100.00","payment_request_currency":"example payment_request_currency 103","payment_request_description":"Top-up Payment","payment_request_metadata":{},"payment_request_scheme":"faster_payments","redirect_uri":"https://my-website.com/abc/callback","updated_at":"2021-01-01T12:00:00.000Z"}}
   },
   "create": {
     "method": "POST",
     "path_template": "/billing_request_templates",
     "url_params": [],
-    "body": {"billing_request_templates":{"authorisation_url":"https://pay.gocardless.com/BRT123","created_at":"2021-01-01T12:00:00.000Z","id":"BRT123","mandate_request_constraints":{"end_date":"example end_date 104","max_amount_per_payment":104,"payment_method":"example payment_method 104","periodic_limits":[{"alignment":"calendar","max_payments":104,"max_total_amount":104,"period":"flexible"}],"start_date":"example start_date 104"},"mandate_request_currency":"GBP","mandate_request_description":"Top-up Payment","mandate_request_metadata":{},"mandate_request_scheme":"bacs","mandate_request_verify":null,"metadata":{},"name":"12 Month Gold Plan","payment_request_amount":"100.00","payment_request_currency":"GBP","payment_request_description":"Top-up Payment","payment_request_metadata":{},"payment_request_scheme":"faster_payments","redirect_uri":"https://my-website.com/abc/callback","updated_at":"2021-01-01T12:00:00.000Z"}}
+    "body": {"billing_request_templates":{"authorisation_url":"https://pay.gocardless.com/BRT123","created_at":"2021-01-01T12:00:00.000Z","id":"BRT123","mandate_request_constraints":{"end_date":"example end_date 104","max_amount_per_payment":104,"payment_method":"example payment_method 104","periodic_limits":[{"alignment":"calendar","max_payments":104,"max_total_amount":104,"period":"flexible"}],"start_date":"example start_date 104"},"mandate_request_currency":"example mandate_request_currency 104","mandate_request_description":"Top-up Payment","mandate_request_metadata":{},"mandate_request_scheme":"bacs","mandate_request_verify":"example mandate_request_verify 104","metadata":{},"name":"12 Month Gold Plan","payment_request_amount":"100.00","payment_request_currency":"example payment_request_currency 104","payment_request_description":"Top-up Payment","payment_request_metadata":{},"payment_request_scheme":"faster_payments","redirect_uri":"https://my-website.com/abc/callback","updated_at":"2021-01-01T12:00:00.000Z"}}
   },
   "update": {
     "method": "PUT",
     "path_template": "/billing_request_templates/:identity",
     "url_params": ["BRT123"],
-    "body": {"billing_request_templates":{"authorisation_url":"https://pay.gocardless.com/BRT123","created_at":"2021-01-01T12:00:00.000Z","id":"BRT123","mandate_request_constraints":{"end_date":"example end_date 105","max_amount_per_payment":105,"payment_method":"example payment_method 105","periodic_limits":[{"alignment":"creation_date","max_payments":105,"max_total_amount":105,"period":"day"}],"start_date":"example start_date 105"},"mandate_request_currency":"GBP","mandate_request_description":"Top-up Payment","mandate_request_metadata":{},"mandate_request_scheme":"bacs","mandate_request_verify":null,"metadata":{},"name":"12 Month Gold Plan","payment_request_amount":"100.00","payment_request_currency":"GBP","payment_request_description":"Top-up Payment","payment_request_metadata":{},"payment_request_scheme":"faster_payments","redirect_uri":"https://my-website.com/abc/callback","updated_at":"2021-01-01T12:00:00.000Z"}}
+    "body": {"billing_request_templates":{"authorisation_url":"https://pay.gocardless.com/BRT123","created_at":"2021-01-01T12:00:00.000Z","id":"BRT123","mandate_request_constraints":{"end_date":"example end_date 105","max_amount_per_payment":105,"payment_method":"example payment_method 105","periodic_limits":[{"alignment":"creation_date","max_payments":105,"max_total_amount":105,"period":"day"}],"start_date":"example start_date 105"},"mandate_request_currency":"example mandate_request_currency 105","mandate_request_description":"Top-up Payment","mandate_request_metadata":{},"mandate_request_scheme":"bacs","mandate_request_verify":"example mandate_request_verify 105","metadata":{},"name":"12 Month Gold Plan","payment_request_amount":"100.00","payment_request_currency":"example payment_request_currency 105","payment_request_description":"Top-up Payment","payment_request_metadata":{},"payment_request_scheme":"faster_payments","redirect_uri":"https://my-website.com/abc/callback","updated_at":"2021-01-01T12:00:00.000Z"}}
   }
 }