A very good friend of mine sold his thriving garage business about 5 years ago. He had premises, three ramps and two full time employees. The ratio of hours/hassle/paperwork compared to the fiscal benefit didn't seem to work. At the time of sale, hourly rate was kept down to £32 per hour to remain competitive. That was 5 years ago.
Rent/ purchase of workshop, wages, employers contributions to income tax and national insurance, holiday pay, bank holiday pay, sick pay, etc etc, make employing someone very dear. Pay just £10 an hour, as an employer it costs the company £15 an hour. Then there are tools/equipment, maintainance of that equipment, insurances, accountancy fees, upgrades on diagnostic software and so on.
I'm not condoning high rates, but it needs to be appreciated why those charges can be so high.
I note that some on here charge just £25 an hour. One can only conclude that their overheads must be minimal and they must be serious grafters, working lots of hours to make a living. Doff my hat to you!
Oh, going back to the original post, either something has been missed in communication or they are having your leg up big time. As said, get a written break down of costs and get someone in the know to look it over. (read; post it on here)