Sounds a bit cheap to me as well, I would have thought £200 minimum for a good job, I paid £180 to have a brand new bootlid flatted and painted and couldn't find anyone to do it cheaper, and I did try everywhere I could. And mine didn't need much work where stonechips are going to need flagging out and probably some high build primer and flatting to make good, not sure how much a new bumper panel would be as they probably come prepainted from ford.