So, turns out the answer to that was 'no' then
It was well worth going to — the idea was for instructors to catch up on the latest thinking (EDICT teaching model, changes to the man overboard and turning in confined spaces drills, etc). For me, it made a good opportunity to quiz instructors and trainers on what I really needed to do to as prerequisites to the PBI course.
They had 22 attendees split into three groups, with three trainers per group. That meant a ratio of 2:1 or 3:1 on the water, which was a perfect balance of time on the helm and watching other people.
Each group rotated between RIBs (SR4.7), displacement (Cheverton Champ) and jet-skis (Yamaha & Sea-Doo). All useful experience — as an SR4 regular, the SR4.7 felt familiar but did some things slightly differently, and hardly anyone I spoke to really had significant experience with displacement boats or jet-skis.
My own last displacement time was with a Beneteau 32 in 2008, before that a narrowboat, jet skis (interestingly vague steering around centre at speed, backwards steering in reverse and no neutral, and quite a lot of bite turning hard-ish at speed). So it was good to get the feel for both types, and come away with just enough experience not to be intimidated by them should the need arise.
And at £15 for the day (£30 for the weekend), much better value than the train I took there and back.
I'll be looking out for it next year.