Out of interest I stripped the old switch to try and find out why it had jammed. Not really clear, but there was plenty of evidence of build of crud and burnt material in the indicator switch track (the indicator part just works by a pin sliding between a pair of brass tracks). Getting the swtich apart is easy, so I would recommend that if you occasionally get the fast ticking of the flasher relay, then remove the switch, take the top off and clean out the track. Should stop the ticking and hopefully stop it jamming like mine did.
Of course I have managed to get the steering wheel back on a spline out, so need to take it off again
