It's a really busy nightlife university tbh, there are loads of clubs and themed nights, every wednesday and saturday The Sugarhouse (student unions own club) in lancaster have nights which are usually pretty good. As well as the other clubs, revs etc having nights like 'free ben n jerrys' and free dominos pizza and stuff. There are loads of bars on campus too, free buses to and from the sugarhouse on weds and sat... basically busy! haha.
It isn't a massive uni, it seems smaller because the campus is fairly small, despite there being a lot of students. But it isn't small to the same degree st andrews is, it's medium sized i'd say.
I really like the city, reminds me of winchester or lincoln, it's quite old and traditional looking. Buses are regular from uni and back and don't take too long, 10/15 mins usually. There are all the high street shops you need - no Primark though!
It's a really nice city though, quite cozy. There's a fair amount to do within the uni, there are literally TONS of societies and things, i've never been bored since coming here. The uni itself is pretty modern - all the lecture theatres i've been in are really modern looking and my accomodation has just been refurbished so that's all new too. It has a nice balance of traditional and modern. :P