a lot of insurers will have set rates with the bigger bodyshops and iam sure the assessors should have a half decent knowledge of repair cars to understand what is required to repair a car so i too dont understand how they come to the conclusion half the time.
say 1k-1,5k for new parts from fords, bumper head lights and wings, ive got the rest of the parts to repair it anyway plus paint i'd be looking at 3-4k to repair to to a very nice standard, smoke it for a year or so then get my money back on it or a small profit,
saying that its making more then 15k at the mo