Just got a call from Graham, who's asked the indoor track for prices.
They run an "Le Mans" style race, which put simply is a 2 hour race with 2 teams of 5 drivers, plus other teams. We even get our own pitboard (w00t). My only concern is that 2 hours with 5 drivers per car isn't an awful lot of running time per driver, but it's VTR in reality, so people might prefer that one [/me gets KillNR2003 ready]. This doesn't require booking.
They also run a Grand Prix, or "Ironman" as they call it. At a guess, this will be a 15min+ practise session, with either 1 45min race, or more likely 2 races of about 20min. We could have booked this, but the deposit was £300... we can phone up on the day though, and if available, go for it then.
Last of all, there's an Arrive and Drive, which as the name suggests, is simply a mocked-up race, with timing, most likely no practise, and is probably a bit shorter.
***
Alternatively, we can phone up the outdoor track on the day, and book the slot after 8pm ish, without a deposit, if it's available, and just run that (either GP or A&D).
***
Rough prices:
IndoorLe Mans: £35 per head
Grand Prix: £45
Arrive & Drive: £25
OutdoorGrand Prix: £40-45
Arrive and Drive: £20-25 IIRC.
If any prices are a little steep for anyone, I'm sure something can be done

The best thing is, we don't have to decide until maybe a couple of days before we go, even on the day, but if people can post what they think, it'll help get an idea of what people feel will be best.