Obvs I know no one can give me a precise answer, but are there lots of British babies that sleep through (and continue to do so) at three months??? Did yours? Did all your friends' ?
I ask because I live in France, am British with a french partner. Our children were not good sleepers and we are seen as freaks of nature amongst our french friends here. All the french babies we know all apparently start sleeping through around the 3 month mark, there's no mention of 4 month sleep regression or whatever and most of them apparently sleep from 830 til 830!
I find this odd as I would say at least half of my British friends have bad sleeper! My dp doesn't believe it when I say British kids doing sleep like this and things it's just the people I'm friends with!