They operate on a points score. They check that the original axle and running gear is on the car, or of original spec. They want original engine and box although only drop points for not having it. Original strut or floor numbers and they check the clocks, dash and take around 12 photos. That's the actual list of things they want. In reality the man who came to me checked the chassis number, vin plate, and took pics of the car. That was it. Had issues with the v5 after as logged it as original colour of grey even though the photos show I had just painted it blue!!! Then came back with original engine number even though I had indeed shown them the original engine on the floor but the new engine was in place and that's what he took a picture of. Waste of time, but all done now.