Whoa! I didn't think anyone else remembered this, but apparently so.
The theme went "There's a guesthouse at the seaside, with constant hot water...." and it was a sitcom written and performed by the Grumbleweeds - a group of men who weren't especially funny, and yet I thought it was ace. It was, obviously, set in a seaside guesthouse, and there was much running about in a farcical type way. I think I also remember at one point, someone walked in on one of them sat on the loo. I hope that was part of one episode, or else I've just confessed to a memory that I have from somewhere else that I shouldn't have shared.
My Dad had a few Grumbleweeds tapes, and a few Barron Knights tapes too, so I was fascinated at how they looked onscreen.