Simply don't do what they say they
Simply don't do what they say they will, and don't keep you informed if they change their minds.
On supposed day of install, there was no contact or visit from anyone. Twice I phoned to find out what's going on. Twice I was told they'd phone the engineer and phone me back. Nothing.
They're safe in the knowledge that they've got my money and secured my OLEV grant, so now I can't go elsewhere.
Possibly they're a victim of their own success? Doesn't feel like it though