Obviously we all know that AITF was based off Till Death Us Do Part, but how many episodes were remakes of TDUDP episodes, if any?

I know that Christmas Day at the Bunkers from Season 2 borrowed significantly from the TDUDP Christmas episode from 1966, but that's as far as I know personally.

I don’t believe there were many adaptations of the British stories. I don’t remember seeing any of the British writers getting credits for episodes. Contrast this with “Three’s Company” and “The Ropers”, where the writers of the British originals got writing credits for several early episodes.