I went a couple of times last year with my husband.
The format for both was similar, but they varied the sessions a little. There were 4 hour long sessions, 3 on ice and 1 off ice, with small breaks in between. Trying to recall now - I think 1 was general skills, 1 was a choice between jumps or dance, 1 was spinning and a wrap up and for the off ice, the first time we went it was artistic expression stuff and the other was stretching. Hard work, if like us you're only used to being on the ice for a couple of hours max, but well worth it - we gained so much from them. Good coaches and there are enough of them for the groups to be quite small & you're divided out into ability levels. For the first one, we'd both just passed Skate UK Level 10 and coped fine. The other people taking the clinic were very friendly and welcoming too.
Hoping to go to the next one, but we've just had kittens and we need to get someone to pop in to feed them as we live quite a way away! Hopefully we'll see you there!