I was involved in recovering a line of 3 tanks from Pirbright Range, having been shown them in 1975 when I was based at Chertsey as Tank Trials Officer. These tanks had been shot at with a variety of weapons by test personnel from RARDE/MVEE/FVPE/Quinetiq from 1943 onwards.
The first vehicle was the Jagdpanther which had been shot at with Bazookas I arranged for the boys from Duxford to remove the engine. Subsequently I arranged for Bob Fleming to be allowed to recover it for restoration. As you saw at Detling, it is no longer a test target, but a fully restored tank destroyer.
The second vehicle was a RAM2 less turret. I recovered this in 1983 and it has been restored to good external appearance with turret and is on display outside ATDU at Bovington. Most of the restoration effort was filling the 133 shot holes caused by Bazookas and Panzerfaust. No attempt was made to make it a runner.
The third tank in the line was a pilot model M3 Grant with about 400 shot holes from Panzerfaust and Panzershrek. I recovered this tank 2 years ago and demonstrated it with Carl Brown at Beltring this year. Unlike the Jagpanther, however, Carl Brown and I agreed to repair rather than restore the tank. The tank had been used from 1943 to 1975 as a test rig for firing enemy weapons at, subsequently used for testing armoured ammo bins. The chargehand in 1975 pointed out that the Trials Branch Register recorded the tank as "Armoured Test Rig, Wing No 1952, Do Not Paint" as burning paint obscured camera shots of bin tests. He had spent 3 days paint stripping this tank inside and out. He had remounted the turret 11 times after trials went wrong. So the tank has been repaired to running order, but no paint has been added outside and no shot holes filled - they represent the historical provenance of this tank. What other vehicle demonstrates what a Panzerfaust or Panzershrek can do to an American tank? We have also avoided fitting numerous bins and stowage items, as they get in the way and as a test rig they had all been deliberately removed. Basically, the tank is ready again for another Armour Test Rig trial.
So the Jagdpanther and the M3 Grant both started from the same range at Pirbright in very similar condition - collanders. But I wold argue that the M3 Grant has better retained it historic provenance having been repaired as opposed to restored.