is the derogatory term "smeghead" actually vulgar slang? Or was it coined for the tv show? Just curious.

Wish I could help with this one, but alas, the first time I ever heard the word was on the show. Which is not evidence of anything. I suspect it might have been an invention - but then the 'feck' in Father Ted wasn't an invention, so who knows - in the deepest, darkest Midlands and North West of Enghland there might be whole tribes of smegheadders...