No, I haven't been before. I rang the organiser for a bit more information about what happens during the course, and it sounds as if I shall need a rest when I get home! The day starts at 8.30 am and finishes at 6.15, with various activities like technique, masterclasses, orchestra sessions and choir, as well as two private lessons included. I've put down for Alexander Technique too (optional extra) - that should give me a short stress-free breather!
It sounds as though you enjoyed yourself, Cellocase. I'm nowhere near the lofty heights of the Performance course, having passed Grade 4 last March.
Yes, Charlie Cello, they do cater for all abilities, both adult and children. The only thing you have to prepare is material to work on in your private lessons, unless you fancy being a victim for a masterclsass. You can even take AB exams there if you want, and there are other extra optional sessions for grade 5 Theory and grades 6, 7 and 8 aural. This year they are introducing an improvisation course which is open to musicians other than cellists. Have a look
here for information.
I'm really looking forward to going (complete with compulsory home-made cake!)