Only Defiants and Battles make some 3000 examples combined, almost all prior BoB were made. That points to the number of Merlins made, too - UK was in far better situation re. engines than Germany any time in war IMO, both power-wise numbers produced. And then we add what was received via LL...
There appear to have been a whole line of second tier manufacturers that could have had products: Fairey, Bristol.