Sunbeam Rapier? Same engine as the Commer, though usually the 1600 version if it's the early sixties, before the 1725 was introduced across the Rootes range. Only one film I can remember with a Rapier is Village of the Damned.
Great film, it's a shame the wall collapsed on the Rapier!
Well done got it right - film that is, still waiting for the van/truck
The Film was
Village of the Damned, written by John Wyndham - (The Midwich Cuckoos). Which was just on Radio 7 as a play. Very scary as a play and very creepy as a film
What the soldiers were doing was, as they had lost all contact with the village and every thing just seemed to stop. They sent a solider on a rope, so when he dropped they could pull him back.
And as an extra bonus, John Wyndham also wrote
The day of the Triffids (see the film a bit below)
So we just need the vehicle.Let me know if you need a hint!