Moving to Leeds

Leeds has a high unemployment rate so I'd be tempted to start looking now and not set my sights too high at least at first.

Students are only allowed to work for 20 hours p/week while studying (no restrictions during holidays).  So you're probably looking at a zero-hours contract (you only get paid for the hours you actually work).  Without wishing to insult you, you're probably looking at bar/restaurant work.

With regards to accommodation, my advise is to contact the Uni and see what they have to offer; many offer student halls for the 1st year.

I know of the 20 hour rule but does that apply to people from EU countries?

I'm not 100% sure now I think about it (it's been a long time since I was at Uni).  It says "foreign students" and doesn't differentiate between different foreigners. I think the rule is more about ensuring they have time to study and attend lectures, than stopping them working.

It it's important that the OP needs full-time work, then I'd probably add to check with the Uni.

Regarding the flat, You should try to find it before you move, it is much better.
I think you can find work in Italian's restaurant.