If you are looking at craft paints, Boyes have them near the knitting wool (may not be in all stores) and cheaper than Hobbycraft. They used to stock Anita's but I think it's a different brand now. They seem to have way more pastel coloured stuff than dark ones.
They may have those small plastic boxes (A4, A5, A6 etc) that Westons make. (Scarborough branch has been out of stock on most of the boxes for about a month, but found at the weekend that Bridlington have stacks of the things.)