The fact that the Mk 2 was not yet airworthy would have been a commercial matter at that point rather than a US/UK relationship issue surely? I don’t see how the US Government were responsible for the faults at that point, and any attempt to lay blame for the crash at their door would have received short shrift. Similarly any attempt to blame Boeing etc would have led to the whole situation regarding the trials at Boscombe Down quickly becoming public.
The whole situation went pear shaped when the aircraft was released to service. What was the motivation for that? Showing off to the Army all seems a bit flimsy as a justification, and I doubt whether any of the SLF on the fateful flight knew or cared whether it was a MK2 or a MK1. Was there a big picture justification at all, or was it overzealous showing off to senior officers?
I am wondering whether cock up preceded the conspiracy.