The RAF pilots were most polish and czechs !
Oh really? Not according to the roll of pilots that I've seen (see below). Note that British also includes a relatively small number of Commonwealth pilots with British passports.
British 2340
Americans 9
Australians 32
Barbados 1
Belgians 28
Canadians 112
Czechoslovakians 89
Free French 13
Irish 10
Jamacians 1
Newfoundland 1
New Zealanders 127
Polish 145
South Africans 25
Southern Rhodesians 3
TOTALS 2936
Certainly the Polish squadrons were recognised as being something special by the British Pilots. The other acknowledged contribution was the tactics that the Poles and Czechs in particular brought in dog fighting from the Polish pilots who had fought the Lutfwaffe in the early days of the war. The change of tactics saved many lives.
To conclude, all pilots who fought in the BOB were selfless and brave and we all owe them a debt of gratitude.