Sorry about that. I've had a look, and for those coming from the south it's exactly the same mileage going to the Tesco's in Buckingham or Cherwell Valley. For those coming from the northwest/midlands it adds 3.5 miles to the trip. Personally, if it cuts out the waiting in queues for an hour or more through being able to get into Silverstone through a back entrance (it's not through those forests, I've checked!) then it's worth it.

I'll put a proper meet-ups post in a bit.