Tony - the background colour is perhaps not the best, but think the pattern is probably legible enough - black or charcoal is better for clear glass, usually, and lighting needs to be used carefully to avoid that glare bouncing back from the glass.
Have you tried the 'Replacements' sites and/or the Board's 'Glass Gallery Crystal C5 catalogue? As you'll know, there are many, many hundreds of cut patterns/designs, and unless someone recognizes this one, you could be in for a long wait.