I very much doubt you'll be able to buy it here. I'm originally from the UK and have never seen it for sale in shops there either -- UK being more likely to sell such stuff.
I guess your best bet is to order it on the Internet and have it delivered. Alternative is to go to a small independent paper producer here and have it custom cut (which I doubt is worth anyone's while).
I have just checked eBay in the UK and there's one seller there:
http://shop.ebay.co.uk/i.html?_nkw=u...tter&_osacat=0 --> as long as it is less than around £20 you'll avoid paying VAT when it comes to Switzerland.