Many thanks for the comments. The tablecloth is a procedural texture but I've solved the edge problem by using a bitmap instead. I'll try a cloth bump, but I originally thought this could be one of those plastic tablecloths you sometimes see in cheap cafes :-) Needs some specularity if so. I also need to think about the liquid, it's too bright as it is. Both bitmaps are mine - taken in Gibraltar, the backdrop is of the botanical gardens, the postcard is the cable car taken from the top of the Rock.

Steve