I am currently writing an interface for a customer who uses Sage50.
I'm currently using a "Sage Business Cloud Accounting Start"trial account for testing.
After some fiddling I think I've got the oAuth2 side of things working and can succesfully call the /countries endpoint in my code. I made some dummy invoices via the front end of the Sage website and can view those via the /sales_invoices endpoint.
However I can't see any way of creating products from the front end and when i call the /stock_items endpoint I receive:
"MethodNotAllowed"
"Action restricted for Start in United Kingdom"
Any idea what I'm missing?