Unbelievable poor workmanship and quality control.

My insurance company I use CK Coachwork Express to repair my Luxury car. They sent my car to another branch and it took 2weeks for them to do the work but when it cam to getting the car, they were delayed by a further 3 days, then a fourth and finally a fifth. Upon collecting my vehicle from CK Coachwork Express, I could not accept the level of poor workmanship pointed out all the faults including the mechanical noises from underneath the car. They were apologetic and asked to hold it another week. A further week passed and I when to collect my car but the workmanship and mechanical problems were not resolved. The manager said he would attend to it and they kept the car for another week. I then went to collect the car on week 5 and to my surprise they had made some progress but the workmanship and mechanical repairs were not complete and so they have now had my car for 6 weeks and it is not looking like I will get it back for another week. They have failed to attend to all the repairs and their workmanship and quality control is shockingly poor. My insurance company are sending an Assessor to collect the car together with myself hopefully in a weeks time, maybe longer?