It really depends on how happy you are with the offers you got. I applied straight after A-levels and got into Edinburgh and Loughborough, but decided I wanted to try again for Slade. Are there more competitive colleges you would prefer to go to? Was Leeds or Bucks New your first choice?
To most people I would recommend doing a Foundation as many people find it very rewarding and it often changes people's whole outlook on art.
However, I did not have this experience. I'm on a Foundation course at the moment and really hate it, it's just a waste of time and I've ended just putting my portfolio together at home (I barely even go in). Most people I know have dropped out and the only reason I haven't is because I hate quitting.
But I wouldn't hang around if I had to pay for it.
As you live in London, you should have access to a lot of good foundation courses though. I've heard good things about St Martins and Camberwell, so hopefully a rubbish course wont be a problem. St Martins is also really well known for fashion if that's the area of textiles you want to go into.
If you think you will be happy at Leeds or Bucks New, I'd say go for it, but if you don't think those are the right courses for you, then I Foundation course would be the best route. There is also the option of taking a gap year to work on your portfolio without a Foundation, if the cost is too much. However, you won't have the same space and facilities offered on a Foundation.
Good luck with whatever you choose.