I lived at Carharrack in the early fifties when the village had its own garage and filling station.
This garage had its own scrap-yard. In this yard were 4Duques
3 Dodge lorries and 3 jeeps. All of these had the white star on them.
I can only assume that when the Americans left for the D-day landings these vehicles had some fault with them and were left behind.
Two of the duques were repaired and taken to Marazion and used for sight-seeing trips when the "Warspite", ran aground in Prussia Cove.
As for the camp at United, many features remained until the late sixties.
In front of the stamps engine house was the bases of the officers huts. these had the names of these men scratched in the concrete, there were also lots of other things like old tobacco tins and corn-cob pipes to be found.
One thing that still remains is the sump oil dump, hundreds of gallons of oil must have been dumped here as it covers quite a large area
In the late fifties the TA had a large camp here. And I can remember old coal fired camping stoves being thrown down Poldory engine shaft before the camp moved on.
As for vehicles being dumped down shafts, with the exception of Man-engine shaft I doubt if any of them were big enough.
Even if they were, these shafts had protective walls around them that showed no signs of disturbance.