Firstly I'd check at your local rink to see if they have a recreational hockey team and/or practice nights.
I live in Essex and skate in Chelmsford, but I know there is a recreational team that take on beginners in Alexander Palace, North London. While this doesn't help you it just may be worth looking at other rinks in your vicinity if there is nothing at your local rink.
Some clubs may have equipment that you can borrow for a while, some players may have excess kit that they don't use any more. If you need kit either initially or later on, there's always ebay!
NISA have changed the SkateUK levels so some requirements for the old level 4 may now be in level 3 depending on what syllabus your coaches are teaching, so your skating abilities are hard to access from behind this keyboard. But if you can skate forward at a reasonable rate, backward c-cuts, turn (mohawk) from forward to backwards, and stop, then you're well on your way.
This site may help
http://www.youtube.com/user/juvenilee6videosAlso
http://howtohockey.com/Good luck