I should have done this ages ago but Ben Baldwin, who supplied the cover artwork for The Mask Behind the Face, has an online gallery. You can check out his book designs here.
Obviously the only cover you'll be interested in is the one for Mask but you can look at the others if you want :-)
Actually, I just realised that Ben's using an early version of the Mask cover design in his gallery. Quotation marks round the tagline and an abbreviated quote from Mark Chadbourn that misses out the bit where he specifically recommends buying the book. If a best-selling author recommends one of my books I want people to know about it damn it!
The artwork still looks great though.