[James2001]

I think that's just their standard video format. Looks really crisp and decent quality to me.

The format it was shot on at the time is irrelevant, they will have digitised it from 25 fps interlaced video. The transfer from film took place almost 40 years ago

It wouldn't have the 50Hz movement if it was shot on film though, however good or bad the transfer- and you can see dirt, scratches, grain and weave throughout which are telltale signs it was shot on film (especially on the material from the channel itself, which looks like it was telerecorded- with the right hand side and bottom of the frame quite clearly cut off during the idents and clock sequence, presumably due to how the telerecorder was set up).

I think the reason it looks so crisp is because it's been put through some sort of AI cleaning/upscale process alongside the conversion to 50fps (which I think also helps hide much of the film graininess).