10% redheads in PL
I reckon less. If Scotland traditionally has or had one of the highest proportions of redheads in the world, and this in the 1950s averaged at about 10%, and southern England only about 5%, Poland ought to have less. Probably.
The other alternative is that British redheads are more fiery and they go for the stand up and be counted option!
I don't believe in the fiery redhead thing - I've known fiery people of various other hair-colours. Brunettes dyed pink seem to be the most extreme from my experience!
source of info: Reader's Digest Atlas of Britain, 1965, and from my own experience/brain.