Sounds like a great idea. Although this is not my bag (I’m relatively new to the Spine Core family, I’m a product owner but my work so far has been focused on SCRa rather than APIs, but I’ll be moving on to that soon!) What you need is someone more familiar building things with the Open Test environment)… I’m currently trying to hunt down some people who can help further.
There is something called the Supplier Information Exchange which I’m trying to find out more about for you. That might be a good route in to the right people to feedback on documentation and start to help build something more useful.
Please could you contact email@example.com about the Assurance Support resource been made available outside N3 as they will be best placed to answer. Although I have since found out that the best resource to use for information and tools to help developers create software for health and social care is: https://developer.nhs.uk/
I’ll be in touch when I have some more information.