GREAT vendor. I'm restoring an old BSA Meteor, and they had EXACTLY what I needed: piston buffer, main o-ring seal (X2, because I might cob it up) and a new breech seal. They're in Australia, but shipping was free, albeit about 2 weeks from order to delivery. I'm impressed with what they have to offer for older guns, and the quality of parts looks awesome. If you're not in a great hurry, I highly recommend these guys.
This weekend I'll be going back inside the Meteor and replacing my cobbled-together amalgam of parts I had on hand.
I am with ya, I have bought several HW seals of different varieties, good stuff, answers emails well.