Boiler Gas Valve Coil

I have a Glow-worm Hideaway 80B boiler circa 1971. It has just stopped working, and the missus is getting cold.

The symptons are: Pilot lit OK / Pilot thermcouple works OK; Both HW and CH controls calling for heat. Main burner won't light;

240V from thermostat is present at gas valve coil plug. Remove coil - it is open ciruit.

Based on above, I assume the main gas valve is not working because the coil is duff. Is this logical? Cost of new gas valve approx. =A3110 + fitting (I assume is a Corgi job: fitting would be dead easy, but correct pressures would need setting. Cost of broken coil? - I would guess about =A32. So question is, does any one know of any supplier who supplies coils suitable for gas valves? Alternatively, is there any reason why fitting a generic 240V coil of approximate same size would not do the trick, and save me a couple of hundred quid at same time?

I'm sure coil failure is reasonably common on these valves, and it seems ridiculous if the entire valve needs to be replaced.

Thanks in advance for comments.