One of our radiators is cold - has been for a couple of weeks since we turned the thermostatic valve back on. I've been putting off ringing a plumber as it takes ages and is expensive.
Suddenly remembered last night that BG 3* covers radiators. Rang at lunchtime - the chap said "is this afternoon OK?" - I said it was and he said ok, some time between now and 6.
5 minutes later the phone rang to say engineer was en route - 10 minutes after that he was here 
- fixed stuck valve one end and leaky valve the other and gave the boiler a quick once-over! How good is that!!!
Must write to one of those consumer columns and tell them!