The answer to your question will depend upon
(a) the type of content you wish to receive ; and
(b) the direction that your dish is pointing.
If you're simply after the free channels transmitted by the Astra satellites that broadcast Sky and Freesat then 28 degrees East is where your dish needs to be pointing to. You'll then be able to receive all of these channels:
https://en.wikipedia.org/wiki/List_of_free-to-air_channels_at_28%C2%B0E
The most popular alternative is probably the Eutelsat Hot Bird group at 13 degrees east. The unencrypted channels available are shown against a cream-coloured background here:
https://www.lyngsat.com/Eutelsat-Hot-Bird-13B-13C-13E.html
(If your receiver and TV set have got HD facilities you can also receive the channels shown against a pale blue background).
The only other principal alternative, with a footprint that covers the UK, is Eutelsat 5 West A at 5 degrees West. See here for the channel listings (using the same colour coding as above):
https://www.lyngsat.com/Eutelsat-5-West-A.html
(Note, however, that there are 4 separate beams from that satellite, with only 3 of them directed towards the UK
https://www.lyngsat-maps.com/Eutelsat-5-West-A.html , so it's unlikely that the North African channels in that list will be available here)