Decide between options you keep going round on

I keep going round in circles on this: whether to move out of London or stay another two years

The options: Stay: keep the flat, keep the walk to work, keep seeing friends midweek.
Move to Sheffield: bigger place, near my parents, two hours from everyone I know, and I'd be commuting down twice a month.
What matters to me: I want to stop feeling skint. But I've moved four times in six years and I'm tired of not knowing anyone.
Deadline: lease is up in November, if I do nothing it renews for a year

Don't tell me what to do yet.

First, make the strongest honest case for each option, in turn, about a paragraph each. Argue each one as if you believed it. Use what I told you matters, not generic reasons.

Then:
1. What I'd have to find out to be sure, and whether it's actually findable before my deadline. Cross off anything I can't know.
2. The thing I'm treating as fixed that might not be.
3. Which parts of this are reversible and which aren't, because that changes how careful I need to be.

Only after all that, give me your call in two lines, and name the single strongest reason you might be wrong.

If this decision touches money, health or anything legal, keep it to plain explanation and tell me what to ask a professional. Don't give me advice on those parts.

What you get: A real case for each option, what would settle it, and a call with the reason it might be wrong.