Ability to complete end to end testing against your Test environment

We have been using HM Land Registry Business Gateway APIs to automate processes for our users.
However, end to end testing is becoming difficult in your test environment as the test data/ title numbers are not fluid throughout the APIs, it is impossible to run end to end testing using your customer testing documents.

Official Copy Document Availability API test documentation says to use title number GR514442 and all documents are available, however when I use the Request official copy api (Official Copy Title known), GR514442 will not return the register and title plan documents together. I have to use a different set of title numbers; ST500681 works for Request official copy api, however that doesn’t work with the Official Copy Document Availability API it returns a 404 error. Please can you provide one title number that you can run an end-to-end test where you can see documents and request them using the same title number?