My tap seized up a while back. It looks like a similar model. I found a spare part pack at Nick Cox chandlers at the Yacht Haven in Lymington which included washers and O-rings. I managed to work out how to take the tap apart and then fixed it. The tap has been fine ever since.
It seemed to be a standard pack so other chandlers probably stock them. I think I saw them at Force4 in Lymington as well.
Good luck.
Terry Gates
"Kitty" P21 No. 99
Terry Gates
"Kitty" P21 No. 99