I don't know if you are aware of this website mybuilder.com, it's a site where tradesmen advertise and they get feedback from jobs they have done in order to increase the potential clients confidence that they will be hiring a decent tradesman who isn't a cowboy.
I put an advert up a while ago looking for a builder and arranged one to come out to meet me but he never bothered turning up and didn't even call me. I couldn't leave negative feedback cos I hadn't 'hired' him yet. At the time, I looked at his feedback and someone else that week left him negative feedback as he didn't bother turning up for a job they'd booked him in for. So his feedback was less than 100%. But I just went on to the site there a month or so later and his feedback is back at 100% and the negative comment has mysteriously disappeared!!!
So don't rely on the feedback! Not a very good website IMHO as it really could be cowboys you're hiring.