The unexpectedly difficult procurement of 30 cm square canvases.

So, I'm partway through a series of (many) 12" or 30 cm square box canvases showing disconnected bits of a town (Basingstoke, where else?), and I run out of canvases. I'm not making them, and Hobbycraft don't have 'em on special offer, so they're too expensive. Off I go to eBay. First order of six never turns up. Refunded without comment by the vendor. Second order turns up yesterday but they are too big - six 40 x 40 cm box canvases. Lovely, but wrong.

I'm waiting for the vendor to respond. Kind of hoping to be told that I can keep the 40 x 40's ...