scotbill
I too had heard the stories about the 121 visit not being returned. Although the supposition does align with the then very "British" way of doing business, passing on plans and ideas to the competition - how many times have we seen that? Perhaps someone with connections from around Hatfield could throw some light on it?
So meanwhile, regarding your theory:
So, arguably, the DH121 was the most influential British aeroplane of all time!
Yep, I'll go along with that!