Seem to recall it had at least one character in the first couple of seasons, played by Kris Marshall. Generic well-meaning idiot son he may have been, but when even he jumps off the ship, you've got to start questioning what's actually going on. That said, I'd still hold it above Mrs Brown's Boys.
Since the thread title is about Rodney, probably worth mentioning Nicholas Lyndhurst's 'After You've Gone' which apparently had 25 episodes. Amusingly, its Wikipedia reads like that Norfolk Lives summary of 'Knowing Me Knowing You' where it blames the show's low ratings on clashing with News at Ten at its peak:
Someone often seems to use a certain word quite often.