I forgot to mention I had a slight leak from the radiator (from the pipe on the opposite side to the thermostat) which I tightened and the leak stopped, when I tried to next use the radiator and found it wasn't working the first thing I did was loosen the nut I had tightened, this didn't work...
I have one of those shiny towel radiators in my bathroom that just does not seem to want to work, in total I have 9 radiators and the other 8 work fine.
Any ideas and thanks for any help!!