I live in the UK and as far as I know there's only one place to get them from, and that's the Avon Valley Cyclery (sp?) aka foldingbikes.co.uk based in Bath. I can highly recommend them as they were very friendly, helpful and courteous.
More importantly I'm happy with my swift. I have yet to take it on a longer ride yet but so far I can pretty much see it substituting my current full-sized bike.
In short, I love my swift and can't wait to use it more, in earnest!