I think he does well as many Indy’s or BMW specialist will not deal with Z4 E85 E89 roof issues or if they do charge a lot for it, where his prices in comparison for those issues seem reasonable. He has a great market, it is a shame he cannot put his hands up when in the wrong and pick up the phone, there are no excuses.
If anyone on this forum does have a roof issue, search this forum there are some great members on here who are very competent fixing the issues and very helpful