Hi Smidge,
             I've seen it in several places including Fereteria Rodrigues Garcia in Tortosa for e21 per pack ( on sale ). Each sheet is 106cm  x  40cm and there are 7 sheets in a pack. There are also special screws that you buy, by the same company, that work well with the sheets. It looks really well and seems simple enough to install and also the small size of the sheets mean if one gets torn off or damaged its easier and cheaper the replace than say the 2mtr  x 1 mtr type sheets of other products. I'll be doing it over Easter so I'll post up how I get on. :)