Ant - basically the day gets broken into half hour driver only sessions, followed by half hour passenger sessions. You can pretty much go straight from the track back into the queue with a passenger if you are that keen (and your brakes are up to it).
I'd say we got close to 3hrs track time. Put it this way - Both me and my brakes had had enough of track driving by the end of the day! There wasn't really any dickheads - mostly the day is about guys bringing their families along and showing them what its like on the track - or people to have a feel for it and see if they like it.
With all the cars on the track its hard to get a good run. We were passing up to 20 cars in one laps! But it was fun. It was different fun to a usual track day as you had to take a totally different line cause you were always passing people.