No instruction this time, it was booked up. So I was just making it up as I was going along - which is definitely what was wrong
In retrospect, and in my uneducated opinion, I was being way too aggressive to start off with. Too much throttle, too much angle, slow hands. When I calmed down it started to make more sense. Also the surface was EXTREMELY slick. Even when it was dry, in a car as powerless as an MX5, you could easily break traction - so as soon as they wet it, it was very hard to catch the car (for a novice at least) if you went OTT.
What I would say is that for someone like me, who is not in the least bit interested in drifting as a sport, it was incredible fun and a nice alternative to the usual track day of just trying to go as fast as possible. it's nice to be able to get it wrong and not worry too much (my mates in the GTR and Gran Truismo were a bit more careful than me!). As you can hear from the footage, we had a laugh all day and I used about a quarter of a tank of petrol (normally track day involves a top up at lunch time) and because they soak the track, I don't think my tyres even got that much abuse - I will measure when I wash the mud off the car at the weekend.