I recently came across a video on YouTube (admittedly 9 years old now) featuring Steve Furber discussing the development of the BBC Micro and BBC BASIC. From my perspective this is one of the most accurate accounts (as it should be, coming from the horse's mouth) of the interplay between the BBC and Acorn in the development of both the machine and the language. It hopefully kills the myth that the BBC didn't really contribute in the way I and others have claimed.
https://www.youtube.com/watch?v=y4WG549i3YY