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