Working holiday visa is probably what you'll get. For a work visa i am pretty sure you need an employer to sponsor you. I just got back from my 2 years in may.
What kind of work do you want to do? Jobs were pretty scarce in london when i left, a lot of friends moved over and most of them have come back cos they couldn't find a job that paid enough to live in london. London is extremely expensive.
It's not impossible to survive, but it's really difficult if you don't have a good support system or money saved.
If a friend was wanting to go over now, i'd definitely tell them to try wait out the recession a bit. Job market in london is extremely competitive, even for minimum wage jobs.

The best areas to live imo are in the northeast, or the east or the north, and try to stay within zone 2.

I wouldn't do that swap thing, it's not necessary, the only bank account you can open when you're not in the uk is an offshore acc or sthg. And that's a really shitty acc, high charges etc.

You can open a regular acc with an address and your passport

London is pretty much the most awesome place, it's hard, but if you can make it it's so worth every sacrifice

what about other cities in england? cheaper than london?

Manchester is AWESOME for music and the nightlife and shopping, and MUCH cheaper than London. I lived there a while and could advice you well on where not to live etc Jobs canm be a pain there though as it is student heaven so there is a lot of competition.

I live in York, which is probably second only to London for jobs... it is only a tiny city but very beautiful and historic. It is England's second most vistied city by tourists too so it is always bustling. If you want to live somewhere big though, I'd avoid it

There are places like Liverpool, Nottingham, Birmingham, Newcastle in the north and Bristol, Guildford, Cambridge, Brighton, Canterbury in the south... you'd need to find som,eone that knows these though, or do some online research

For what it's worth, i had a great time in liverpool... If i was going to live outside of london i'd go to liverpool... Dunno about jobs but literally every single person i met there was excessively friendly. And it was much cheaper than london...
(I'll reply to your pm when i get on my computer)