Hi Keith:
I am quite sure you are correct. If I could find someone about 18" tall and handy with wrenches, the tap assembly could be changed in minutes. I happen to be 6.3" and weigh 200 lbs and as I said in my original post, I can't even feel the underside of the tap.
I think ( with fingers crossed) that I may have solved the problem. The tap has slightly leaked for months and the washers, the "O" ring on the stem and the packing washer all seem to be non standard modern sizes. The original flat washer is designated "0" 1/4" and this size designation is still available today, but it is now converted from metric and is a full 1/32 bigger than the original. The same applies to the O ring and the packing washer. I have lost count of the hardware and plumbing shops that have
sold me the "nearest" size. Consequently nothing fits exactly.
I was talking to a friend today and he had read my post. He is a retired hospital maintenance engineer and he suggested I lubricate all the rubber tap parts with "O" Ring Lubricant and he gave me a tiny bottle of it. I coated the three rubber components and the tap now glides open and shut like silk and makes a complete seal.
I was so thrilled with the result I coated the two "O" rings in the shower head on - off button that has been very stiff for years and that also now is as smooth as the day it left the factory. My friend assures me the effect will be long lasting and the bottle, (about 2" high) will last for years.
I feel that I have discovered a magic plumbing potion, and I very much hope that it has permenantly solved the problem.
Thank you again for your thoughtful comment.
Colin
Colin