DRK, The reason the crowd was so small this year was that the police closed the access roads, so the only spectators were the 400 "invited guests" plus the enthusiasts who had to walk many miles on foot to see the flypast of the Derwent Dam.
I remember the 1993 event very well and I took my two (then teenage) sons out of school for the day so that they could witness it. Their headmaster agreed with me that they would gain more seeing this event, than they would lose in a day's schooling. There were so many people at the 1993 event that it was chaos when they all tried to leave in the late afternoon. I understand that by 9pm some people were still stuck there and those without warm clothing were suffering from exposure. Hence the decision to limit the crowds this year. It gets very cold in the peak district.
Yesterday, the Lancaster continued south down the Derwent Valley to Chatsworth before heading East, and there were crowds at many vantage points down the valley.
QNH 1013