Thanks for all your replies..
I've flicked it on/off myself and you can hear the relay click on and then off. The fan doesn't spin at all but did spin a little when he tried it (I believe he did check it with a voltmeter but said the fan was faulty).
Unfortunately he has not called me back...
I have a Baxi 105e combi boiler which has stopped working.
The boiler will not fire up and the 50 deg neon flashes, stating possible flue or fan problem.
I've had a corgi registered friend have a look at it and he checked the flue (okay) so assumed it was the fan. We replaced the fan...