Does anyone know any Lgbt groups near waterloo/ clapham junction

Hey
First thing, I am not out to my parents at all.
I really would like to join an LGBT group near me but I looked online and there was one close to Clapham junction (London).
Unfortunately it started at 6:00 pm and I can't leave at that time without my parents knowing and I can't tell them,
"Oh yeah I'm going to a Gay, Lesbian, Bisexual and Transgender group to meet people like me." I don't know what she would do but I doubt it would be good.

My school has two bi/pan sexual's and two aromantic/ asexual people apart from me. None of them are close to me.
I am still questioning myself slightly but I am pretty sure what I am although I don't quite think I fit in any specific categories (which I'm fine with).

If anyone knows anywhere close to Clapham junction that meets earlier that 6 could you please tell me.
Grazie