Giving my ago away somewhat, but didn't Foggy leave to run the family egg-painting business in Bridlington?
That was the first time Wilde left the show
The second time he came down seriously ill and it was explained that an unconscious, hung-over Foggy was swept off to Blackpool by the local postmistress. There he inadvertently proposed to her in a verbal slip-up over the wedding rings of which he had taken charge "for safe keeping". Foggy did appear in background and back-facing-camera shots for which he was portrayed by his long standing stunt double...
Three interesting facts:
1) Its darned popular on Afghanistan TV (even the Taliban watch it!)
2) Every episode ever was written by just one man - Roy Clarke
3) The three part special where they show Compo dying and the whole grief and fallout was written in three days which includes the time taken to write special lyrics for the theme tune