Question Author
Yes, those fees do add up. I hope they include the fees for the bits we don't see and don't seem to be mentioned - the electricians, gas fitters and other trades that at least need to sign off the work if not undertake it.
In one episode the house was unsaleable as the boiler was just hanging on the wall not connected to anything, the toilet wasn't connected and some of the work so shoddy it was dangerous. The producers had to get the experts in to finish the job so no profit.