PAL standard only applies to SD mediums. Once you move into the HD realm, all the benefits of PAL (higher resolution from more lines in the video source after 1969) and drawbacks (its too fast) disappear.
That said, most British and European television programs of the time made on film were shot at a slightly faster framerate of 25fps using 16mm cameras to make them easier to adjust to the PAL framerate. In HD this has meant either they have to be interlaced or slowed down ironically to the 24FPS standard ala Criterion's releases of Berlin Alexanderplatz and World on a Wire. However As far as I know The Avengers, The Saint, and The Prisoner do not suffer from this problem having been shot on 35mm purely for the purposes of foreign export.
PAL - or 625 line tv started in the UK in 1964 on BBC2 although it was 1969 before the main channels started to change over to it when they went into colour.
With the exception of the ITC shows like The Saint , Danger Man ( and many others) and a couple of ABC series like The Human Jungle and The Avengers UK series made on 35mm were non existent.
ITC shot on 35mm from the start of ITV in 1955 with Robin Hood but as you say , this was for the convenience of exporting to countries using incompatible systems .
Apart from those shows the number of series made on film entirely is also very few.
The BBC usually shot on tape and used 16mm for exteriors but rarely was anything all film.
Euston Films , part of Thames used 16mm purely because it was cheaper and the BBC also used 16mm because it was cheaper and did some all film series in the 70's , many of which were co-funded by European broadcasters.
As far as I am aware none of the all film series were shot at 25fps . They were standard 24fps and like US imports were speeded up for UK consumption .
When Network released The Sweeney which was made on 16mm one of the things they looked into was the possibility it was 25fps - but it wasn't.
Space 1999 was also shot at 24fps - which meant that before production started Gerry Anderson ensured that the numerous monitors on show in Moonbase Alpha were adjusted to 24fps to avoid the onscreen interference you would get shooting 25fps UK monitors at 24fps.