The social life at BA is pretty good, but like everything it's pretty much what you make it.
The best thing about BA is also one of the worse things about it. It is totally seniority driven for promotion, transfers etc etc. But that also means that there isn't much bitchiness, backstabbing or brown nosing amongst the crews cos there ain't no way you can get promoted til your seniority number comes up!
A great thing about BA is the range in the crews ages, backgrounds etc etc. There are loads of young crew in the 800 or so that have been recruited within the past year and plenty of umm more 'mature' crew as well to balance things out.
The compass centre (crew centre) is always full of ads for flatshares and accommodation and as there are always plenty of courses starting and new crew coming from all over europe/UK to be based in London looking for a place to set up as well.
Good luck!