I’m not familiar with the model Andy but it will likely be blocked jets which is the cheapest problem as it should be a simple case of clearing them/it or replacing which shouldn’t be too expensive.
Then you get into the expensive stuff, FSD, burner assembly or gas stat none of which you will see change out of £100-150 to swapout.
Well, I thought I would at least have a non disruptive look. The jet is visible in the side of the grill compartment. A gentle clean with a small wire and the grill is back in business.
Future readers take note that probing a gas jet with any rigid object is not to be recommended as there is a significant risk of damaging the jet orifice and upsetting the air/gas mixture. The task should really be left to a suitably qualified – CORGI – repairer.