Flora, the callers this year are
Colin Hume, Dave Turner, Geoff Cubitt, Hilary Herbert, (Janice Kilroy & Pete Jones), Jerry O'Reilly, (King Kontra), (Les Barclay), Martyn Harvey, (Pete & Marj Hendy), (Will Hall).
Some will be calling Downstairs, aimed at experts and serious dancers Playford and American squares and contras.
Upstairs in the Pavillion the early evening Ceilidhs attract a lot of people who know what they are doing, but the callers should (and often do) explain things so that those who are alert but less expert can enjoy it. They call them 'ceilidhs' but can include a mix of styles, like a dance club.
Later in the evening it may be more Ceilidh.

Colin is an expert caller, always clear - Playford, American squares, traditional dances (if he does a mixed programme he always includes one of the old dances). When he's downstairs and doing a programme billed as "Squares (or whatever) to make you think" he means it.

Geoff Cubbitt specialises in American, particularly Contra. Another excellent caller. His upstairs Contra Ceilidh is well explained.

Hilary likes hard dances, she writes them too. She's well known for it so the people who go to her events tend to also like hard dances. She likes to interact with the audience. Very clear and seems to know what is going on in all parts of the room.

Martyn Harvey is the expert Ceilidh caller. Really good at that side of things.

All of those 4 can adapt to their audience and are worth learning from

Jerry o'Reilly teaches (not 'calls') Irish Set dance. If you go to his Irish Ceilidh you need to know the dances - or listen to the songs and watch the dance spots. Also a good singer.

The names in brackets I don't know enough about to comment - some I can picture, some might be musicians for all I know.