I've got a loss of power on my car and 2 error codes (maf & map sensors) and so I've told CM when I booked a power inspection (£68). In my stupidity, I actually thought that the mechanic sent by them will diagnose and point to the exact failure. Instead, there comes a mechanic with his own tester and, after aprox 1/2 hours tells me the exact same thing that I told them. His suggestion was to try and replace the maf sensor, then see if it works better. If not, replace the map sensor as well. I didn't say anything, I let him go and he went away. Needless to say that if I wanted to go his approach I could have done it myself. Later that day I've opened a dispute to try and get my money back, money that I've realized I've paid for nothing. Of course, that didn't happen. I only got almost half of them, and the reason the mechanic selected on the CM site was that I have canceled the appointment. My advice: just avoid and go to a real garage, any garage.