Shw mae, Sweetleaf. 

I'm not based in Brighton, but I run a free Welsh course at www.SaySomethinginWelsh.com which will really get you speaking Welsh.  I notice that we have an advanced learner in Brighton who might be willing to meet with you to chat as well.

Have a quick look at the site, and if you're interested you can download all 33 free conversation lessons whenever you like!

I hope that fills the gap if you still can't find a tutor.  All the best

Iestyn