A YouGov poll on attitudes to swearing on tv found that 38% of people thought that the word pimhole should be broadcast only after the watershed and 23% thought it should be totally banned on the television. The survey suggested pimhole was regarded as being more offensive than words like bollocks or bastard.
Pimhole is a real place in Bury, Lancashire; it was also used as a made up swear word in a Fry & Laurie sketch on tv 20 years ago.
Perhaps some respondents had a vague memory of the sketch, or know of Pimhole as a somewhat rundown area in need of regeneration, but since they were reacting to a list of words presented to them by the pollster it is possible that they just thought that it sounded rude. And orifices are of course always good for a titter.
I suppose one useful test of real acceptability, among radio listeners at least, would be to get Jim Naughtie to say it on the Today programme.