They were all filmed in 5:4 or 4:3 back then, but with production quality cameras so you couldn't fault the quality when they released them online.
Original video grab (720x576)
Then they fucked up the HD release and stretched the films to 16:9 (1080p), so everyone looked 4 stone heavier.
Who ate all the pies (1920x1080)
The second batch of HD released were also 16:9, but to compensate they cropped some of the screen, then stretched what was left. They looked 2 stone lighter but still a bit wonky.
Getting there (1920x1080)
They finally sorted it out and re-re-posted the de-interlaced, remastered originals with the aspect ratio they were filmed with, and those are back to normal.
Hallelujah (1440x1152)
I've downloaded a mix of those bodge jobs and SD versions over the years, and the ones that were stretched and/or cropped, I fixed myself. Meant another render but they came out fine.