As I understand it the majority of the Dr C Dresser Clutha items were marked, but the designs by George Walton were certainly not. Of course that doesn't mean if it's not marked it's by Walton, so be careful.
Over the years I have been lucky enough to own three pieces of Clutha glass, all unmarked, only one being by G Walton - but 12 inches high!!! 'Wish I still had it, that's the sad thing about dealing in this wonderful stuff, it has to go, so that the bills are paid. On the other hand it does allow you to go and find something else that's great
I believe that Harry Lyons is continuing his research into all that is, and was, Christopher Dresser. His work, and others, on Dresser has made collectors and dealers far more aware of how important a designer Dresser really was, giving us an insight into how influencial he was upon later design and design movements throughout Europe and the UK. I thought that it was sad that his collection at Christies sold so indiscriminatley. There were certainly bargains, but fortunately there were also some highlights.
However, watch that space - I'm sure Harry will give us more to marvel at sometime in the future. I wish him lots of good luck in his endeavours.