I didn’t see this when it popped up last Christmas, so apologies if you’ve already seen it. There was a time before Only Fools And Horses was the tune-in event come Christmas, and so they were relegated to appearing on other shows instead. After the end of series 2, in 1983, that meant this happened on Russell Harty’s Christmas special.
https://youtu.be/ZnqgvL_jhJ4
Anyone know if this was written by John Sullivan?