Aussie Andy, Yes, I'd say any visit is worthwhile, but with only half a day you'll be limiting what you can see. You can probably whizz round the exhibition/trade stands in that time, or run around the parked aircraft (could be upto 1000 (yes 1000)), but not both.
Are you going from Booker or Benson?
I'll be driving over (from Chalgrove) on Sunday, so will try and find some of you lot during the day.
Brooklands