fastmongrel
1st Sergeant
I'll think about it a little more when I get home, but first thoughts would go to the P-47, F4U (Cannon versions), or Tempest. All three packed one heck of a punch, could climb with the best of them, could dogfight (the Tempest not so much), and had the ability to stay in the air for extended time when equipped with drop tanks. That's just my first thought. There may be better at destroying bombers and I just haven't thought of them.
I always thought that at its best altitudes the Tempest was reckoned to be a good dogfighter. The altitude problem was the lack of a good high altitude supercharger caused by English Electric having to force Napiers to concentrate on reliabilty first rather than developing hotter and hotter versions. Very late prototype Sabres had a 3 stage (or 3 speed 2 stage not 100% sure) blower that might have got the Tempest high enough. For real punch to knock out bombers the RAF already had the Vickers 40mm S gun which had originally been designed as an anti bomber gun before it was turned into a ground attack gun.