I only had one for repair. I didn't come into the repair game until the mid 70's so maybe there were more to be attended to before then. I cannot recall exactly when it came in as I had the shop from 1979 to 2003 but it was brought in whilst the shop was under my ownership. Certainly a good deal of years ago.
The problem with it was the most absurd repair I've ever come across. The owner said the plug had never been attached to the mains lead all that well (it was such a common occurrence in the days when appliances did not have factory fitted plugs) and on the last occasion the cleaner had been used prior to coming in for repair, the plug had come right off. I am not all sure whether this was as the lead was being pulled out by the user, or pulled back in by the cleaner, but as you will know, the design of the retractable lead on the Hoover Celebrity was such that the user had little control over it; there was no button or lever to press, one just tugged on the lead and in it went. So some how the plug came off and the lead shot back into the cleaner. What I do remember is the woman who brought it in saying that it made the most horrific noise as the end of the lead disappeared into the cleaner before her very eyes.
The cleaner came in with it's hose too. I distinctly recall the woman saying "we didn't know if you needed this" as she gave me the hose, because there was what I later discovered to be an air-powered on/off switch on the hose. I saw the button and at first glance had no idea either as to whether the hose needed to be connected to start the cleaner, which again as I later found out, it doesn't.
I don't recall a UK cleaning having such a feature until the arrival of the Sensortronic range, and even then it was powered by electricity, not air. The positioning of the on/off switch on the hose was such that I thought it to be jolly awkward to operate, and indeed by the time the user had moved the hose to such a position to get to the switch it would have been a good deal easier to just hit a switch on the cleaner with one's foot. But that was Hoover for you, ever on for a gimmick. Note that the hose on these cleaners from the USA did not stretch, which at the time would have been a disadvantage over UK models as Hoover always made such a fuss about their extending hoses. Having said that, Hoover were just about the only manufacturer to have such a feature on their cylinder cleaners (and indeed uprights for that matter) and when you consider the millions of none-Hoover cylinders with rigid hoses sold at the same time, it begs the question "did the consumer really care that much about a stretch hose"? I am inclined to think not.