I have no idea how many UK members are on this forum, but for those who are here and - like me - have had some difficulty finding thick heavy duty (1mm - 1.5mm) card, the following may be useful. Postage rates aren't too painful, they will send samples if you want to check out something first and the prices are excellent. With the proviso of course that the place specialises in re-cycled card. There are other weights available, so ordinary card from around 150gsm and up are available, prices likewise are extremely favourable. This is one of the very few places I've found that carries 1mm in A3 and A2 sizes. There's paper, envelopes and all sorts of other stuff on the site, but here's the link to the card section. Hopefully this helps somebody. Eco Craft Online Store 1 and 1.5mm card is towards the bottom of the page.