I'm sure they practise for a good few months - possibly 3 or 4. And they are probably having at least 2 hours of one-to-one tuition every day, maybe more if they've got time. So they've probably had more coaching (and ice time) by the time they start, than we do in maybe 2 years!
That makes me feel a bit better when I see how good some of them are
I agree it's been good to see several of them looking quite strong, and I think Sinitta should have stayed as well. Even with the mistake she made, it seemed a better performance and routine than Sharon's. But hey.
Re an intensive course, I don't think this is quite up to what you're looking for, but I'm fairly sure I remember seeing signs at my rink last summer, where they were offering a week of Skate UK. You had a half hour Skate UK lesson every morning for a week, and then you could stay on for the public session. I suppose it would be like the equivalent of doing a 6 week Skate UK course in one week. I expect all the Planet Ice rinks were probably doing it?