First trip was October 23rd 1966 - Dominie XS730 Ex D1 with Master Pilot Chappell (those were the days!). Ex D2 was XS739, so delighted to see them both at the very end.
Looking through the next 3 months flying, I see that the average flight time was 3:10 to 3:30. When I did a tour instructing in 80-82, my longest was 3:05, which makes me wonder what Div fuel we were carrying operating out of Stradishall in '66. It can't have been much by modern standards! Perhaps recent crews could hazard a guess?