This has got to be a wind up.
Although fitting used body parts would generally be considered ok, i cannot believe that insurance companies are pushing for used parts to be fitted.
In fact, Aviva were the ones who told me not to fit customer supplied parts due to warranty issues in case of a failure.
I tell you what, why don’t we all just slum it and do the job for free. This is just another way of keeping the trade in the dark ages.