A good idea! And pertinent for me at the moment- I have a Kodak Ektar lens in with Newton and Ellis at the moment, for an overhaul to the Prontor shutter its in. I've been using these chaps occasionally for the last twenty years (eek!), their first job for me was to overhaul my battered old Rollei 3.5f which I could barely afford as a teenager, but just loved the look of. They did a great job then, and I since put hundreds of rolls of film through it. They overhauled it a second time when I knocked over whilst it was mounted on a tripod and the shutter release button disappeared into the innards!
They've probably looked at every camera I have owned since, for some job or other, and I've always found them to be superb to deal with, and the quality of their work is excellent. I bought my first Leica from them (an M6 with 35mm Summicron) about 6 years ago, they often have some nice older stuff for sale there.
Two further Leicas have since arrived in my camera bag, and both have been sent to Malcolm Taylor- he cleaned and coated a 9cm Elmar for my Leica III, utterly transforming the performance of it: cleaned and was able to make the best of a worn focussing thread on the same camera's 5cm Elmar, to the point where it operates mechanically perfectly; and totally overhauled my M3 which I've used almost constantly ever since.
In twenty years of amateur photography these are the only repairers that I've needed to use and I've always been exteremely pleased with the cameras when they have been returned. And no, I have no vested interests, just satisfaction. These people are real experts, its nice to have the opportunity to give them the thumbs up in a public forum, after all the good work they have done for me.
Looking forward to hearing about other people's experiences!