Stoves GL716 Oven and Grill - Gas but no ignition?

Hi, I have a GL716 (Mk II) and recently the oven and grill have stopped working - when I turn either on, there is a solenoid click, but no spark and therefore no flame. There is gas as I can light the grill with a taper.

I read other messages on here that suggest it's probably the thermostat switch and a reset should fix it - I removed the appliance and cover to access the thermostat switch but it appears to be of the self resetting type (Elmwood 2455R). I removed the switch and checked continuity - it's closed (i.e. there is continuity), so I assume this isn't the issue.

Does anyone have any idea what else would cause the igniter for both the oven and grill to stop working? Thanks

Simon the Pieman (with cold pies!)
September 2013