You are right, the scrap yard was famous for containing lots of road steam traction engines & rollers also lots of other vehicles, it belonged to J.W Hardwick & Sons, it was in Cocks Lane West Ewell in Surrey. I belive the tank was built by REME from bits left in the factory and I also think there are some records of that in the REME Musuem. Eddie Kenton, one of the earliest liveing history group members of BRA The Battle Re-enactment Association. was involved in it's discovery. I was phoned by a mate who was employed by the famous Quatermasters at the Angel and in the know. We turned up just in time to se it towed out by a Pickfords trailer truck, lifted on by two B----y big cranes, I think it was October 1977? The yard is now covered in houses, all those goodies gone!! Just like Pounds Yard? I wonder if there any like it still out there?
The thread brought back memories, I was 32 and didn't have the wonga to buy a tank so I could just about afford a jeep, now I have the money, can you fit a Stanna stair lift to a tank!!
PS I was right the yard is long gone, they have even done the PC thing and changed the street to Cox Lane to gentryfie it a bit.