Just to set the record straight on new damascus barrels on new WW Greener guns: I wrote a 3500-word feature article on these guns in the Sept/Oct '07 issue of Shooting Sportsman magazine, based on 5 visits to the WW Greener gunmaking workshops over about a 10-year period.
They are indeed newly made damascus barrels, built on vintage tubes that David Dryhurst -- Greener's master gunmaker -- has been collecting since the '60s and '70s. Some are old Greener stock, some are English and no doubt some are Belgian. A few of these sets came from Dyson, but Dryhurst began collecting damascus tubes long before they became fashionable (again). He was way ahead of the curve in anticipating the renewed popularity of damascus. The guns are being made in 28-ga up through 12, and maybe in 10-ga. At least 25 of these damascus-barreled guns are made or are under way, and I believe more have been ordered since I last asked. At the time of my writing, none had failed English proof -- and that is your warranty. The owner must be smart enough to shoot the shells the gun was proofed for. The guns are proofed under standard CIP pressures per the particular gauge. They are not lined.
Most are on sidelocks; some are on reintroduced "G-Guns" -- Facile Princeps actions with Boss ejectorwork. Greeners are a small best maker -- but demand has been so great that I am told they have again closed their order books. They were the last British maker to manufacture their own damascus tubes, and are the first to again offer them in commercial quantities.
The article in not online but a back issue can supply more details, should anyone care to investigate. Hope this helps.