As slim seeker says, don't always go for the big companies. We went for a local company and were very pleased. What you do need to know is that the installer is FENSA registered. It will give you certain guArantees when they are registered with this body. My mother had her flat done with a very local installer 7 years ago and now the leaseholder is paying to have all the others done in the building but but mother's are far superior quality than the ones being fitted to the other flats.