Hello Tony
IMHO your RAF A-36 timetable in your message #
30 is highly optimistic when we think that the first oper. sorties by Mustang Mk Is were flown in May 42 and the handling trials report for Mustang Mk I was completed at A&AEE in Aug 42. Because I don't remember that RAF asked other manufactures at that time to design a dive bomber version of their fighters, why should they asked that from NA. So IMHO earliest possible time for interest in A-36 was when NA got its prelimenary design of A-36 ready.
Juha