Risque humour
I read an interview with one of the Moffats sometime in the early 90s where he spoke about the use of humour in Press Gang. He was saying something about how he wanted the humour to be grown up and sophisticated in order to avoid patronising the viewers and said they were able to slip quite a few in-jokes past the censors.
He mentioned being tempted to write a scene where Colin said to Lynda "I'm just trying to butter you up, not in a Last Tango in Paris way obviously." but realised that he would be overstepping the mark by doing this!