The Sweeny

I'm looking at Internorm windows and have to say many of the approved installers seem to have bad reviews. I've encountered unnecessary obstacles just getting to view the products at the showroom never mind ordering and installation. OH is keen on Internorm but I'm worried the installer will do a poor job/bad service. So with this in mind what installers are recommended? All those local to me get bad reviews. I want to avoid the accident waiting to happen.