... So after some intensive search on Amazon and Ebay, I ended up ordering the medical exam table paper from American Amazon. This one.
I had just about run out of pattern paper and as this was such a good price I ordered some on Monday, and it was delivered on Wednesday, so it only took 2 days to travel all the way from the US to Blighty, which was mightily impressive.
I would definitely order it again, but looking at the amount on the roll I think I have enough to keep me going for a good while yet.
@Hachi - thanks so much for posting the link to the product