I think they have a few other sizes in the shop. Glad you liked them!
A UK 6 should be a US 8, right?
As far as I know a UK 6 is a US 7 as I am a UK 10 which is a definitely a US 11.
Anyway my reason for posting is just to say that my girlfriend bought a size 6 of the boots in the original post in this thread from ebay and they look great on her! They are not leather, but look good enough that you probably couldn't tell unless you were wearing them, or were looking at them close up.