There are some good points here, but TGA need to remember to get some runs on the board with the manufacturers before they can go damaging stuff. eg, the road test Clarkson did the other week with the Ford, yes it would have been ruined, but the idea was fantastic and it was executed brilliantly. I'm pretty sure Ford didn't mind losing a car to that. The lawn bowls with cars by TGA - a lot of damage could have been avoided - proper placement of the ramp and removal of the cars after their "bowl" (yes not strictly the way the game is played, but would have been cheaper). This could have been something done with second hand junkers instead - a la TGUK darts game.
TGA need to be a bit smarter about whether they're using new or second hand cars for the game/challenge etc. The trip up north was done with new cars, and should have been done with new cars, and manufacturers need to (and do) recognise that vehicles are going to get damaged. I'm sure there is a budget set aside for exactly this. What really gets them off side is excessive, deliberate, unnecessary, damage. More care needs to be taken if cars are being privately loaned (ie the GT40) or borrowed from dealers. But if TGA can get some good films together, most manufacturers will grumble about reasonable damage (fair wear and tear), but still hand over cars in the future.