Karnak:
You're right, the Boston Mk III, being a 1942 model, is too fast for 1940 era Axis fighters. Checking the "Illustrated Encyclopedia of Military Aircraft" I found a much lower max speed for the Boston: 304 mph @ 13k. Hmmmm.
Anyway, the B-25c, Wellington, and G4M2 (I wrote G4M1 above; M2 might be better) would all be good. How about the Bristol Blenheim Mk1V, too?
******
In terms of mph difference, the A-4 is only slightly faster than the BoB A-5. But, I figured out once, it means that a pursuing Hurricane I would take 50% longer to catch the A-4. So instead of 6 minutes, it would take 9. It's a judgment call if you consider that significant. I do. Minutes count in air combat.
MRPLUTO