To ask a slightly naive(sp?) question. Do you mean old school cull or just not breed them? Man this may make me soft, but I hope it's just not breed them and send them out as pets.Many serious British lab breeders will cull a chocolate pup. It's the norm in Britain to cull them. If you find one here in the states you're lucky.
From what I understand the english and british are the same. From what I've seen the american is usually the larger of the two with their legs being longer looking. As for the head, I've seen both styles have them, mine doesn't. I don't know what the conformation criteria for the head is.just need to ask is what some call a english lab and others call a british lab one and the same. for i have 6 labs and only thought there was 2 types the english and the american. and that the english has the big block head. where the american is litler of the two with a smaller frame.i do breed my dogs but they are for hunting and family dogs not for show.