It's not so much on a loop as a re-run of the entire series right through from episode 1. Last night's was series 9 episode 2. Which means that there have so far been 76 episodes repeated (which, with various blank Saturdays due to sporting & special events, means it has taken the best part of 2 years to repeat thus far). There are now only 4 episodes left to re-show.
A clue to part of the reason for the re-run, no doubt, is in the title of your concurrent thread "Why has comedy forgotten to be funny".
Quote: smc4761 @ 16th October 2016, 7:34 PM
all of the cast except Ian Lavender are dead, I believe
And except Frank Williams (the vicar), who is still doing the rounds of provincial theatres sharing anecdotes about his life & career. I saw him at the Connaught Theatre Worthing 2 years ago. And he was in the recent film.