Sweeper was probably a Lacre conversion? I have seen pics of others. Southern Gas had mostly BMC group products and we did any major work required on them such as engine changes at our dealership, although their own workshop on Silver Street in Reading carried out the day to day stuff. I remember them ordering some new J4 vans and our painter was disgusted that they wanted a ‘quick spray paint job’ as he did most of the vehicle painting by hand usually! They also had a Morris FFK ‘prime mover’ and trailer which a pair of twins crewed. They were both big lads and the standard seat base was lowered to accomodate them comfortably. The story goes that one day they spotted a lad chatting up two girls on a street corner and the two guys shouted something at the lad in jest. He responded with abuse and the ‘V’ sign so they both lept from the cab and when he saw the true size of them the lad scarpered leaving the two girls standing their on their own wondering where their ‘hero’ had suddenly vanished to! 
Pete.