Wimble Toot
Banned
In the UK there is Sabre in development
Didn't work properly until 1942-3
In the UK there is Centaurus in development
Didn't work properly until after the war because of the need to get the Taurus and Hercules into volume production
plus Merlin 1500 HP or better
More Merlins = fewer Griffons - it didn't produce anything like 1500 HP before the Fall of France - how did the Merlin fares as powerplant in the Fairey Battle, Fairey Fulmar, Armstrong Whitworth Whitley, Vickers Wellington?
Manchester can be turned into, perhaps, maybe, possibly, into a 4-engined bomber. Lets call it Lancaster.
It's an original idea, but it won't catch on.