For my sins, I'd left the Ultremo ZX's on... I'm about to start a new thread elsewhere regarding tyre choices, because using my race tyres wasn't ideal.
In all fairness, I think most of the issues after the first two punctures can be attributed to me, rather than the tyres though. My old CO2 pump broke on the second puncture, so I was stuck using a mini pump (which is OK, but never going to give me 110psi). After the second, I had the tyre completely off, checked the inside and outside of that, plus the rims, plus all of the spokes and there was nothing at all causing the flats.
However, after the first two, I was stuck with patching the tubes that had already punctured, which is never ideal at the best of time, as there's no real time for the glue to go off properly. Managed maybe 5 miles before I could hear the air escaping. By the time I bought the new tubes from the service car, I was so knackered that I just don't think I was putting sufficient air back in, so my last flat was a snakebite from an under-inflated tube. Fortunately I was nearly back at Princetown by that point, so I swapped to the last of my newly-bought tubes and managed to limp in to where there was a trackpump. I was fine after that.