as promised I have found a few of the agencies addresses who also deal with job sponsorship. They havent been any good for us (so far) but you may have better luck- I guess it all depends on your profession
there is also a company called 'free spirit'..we didnt join that agency as they wanted money up front and couldn't guarantee they would find a job for you
I know we have found a couple more agencies along the way, but cant find their addresses at the moment. will post again when I find them.
hopefully some of you who are trying to go down the sponsorship route will have some luck!