Just to add to TB's comments,
Pay as late and and as little as possible up front. Try to get away with just a deposit until you start.
Also, get that VISA in shape such that you can use it to pay for the course. You may be able to get something back it it goes belly up.
PS.
London Guilhall would be my choice. When I was there in the late 80's it was run along very un commercial lines, ie not for profit. Things may have changed since then mind you. It was also a good place, easily on a par with PPSC with whome I was fortunate enough to finish with before they folded.