Hi Coomsey I had a similar experience at Preston Gaol in 1971 - 2 when I had to deliver 6 ton of cement with my ERF 24 foot flat 6 wheeler. I delivered 8 tons to a builders merchant jn Preston then 6 ton to the prison, like you the wagon was too long to be enclosed within the two entrance gates thus I was surrounded by warders and told to get my foot down for a few yards. Prisoners unloaded the bags the supervising warder told me to let them get on with it as I had started to put them on the chock rail. They burst more bags over each others heads than they unloaded when I asked one why they had done this the reply was that they could spend the evening in the showers. My supervising warder was the double of Mr Baraclough from Porridge.
Cheers, Leyland 600.