EW52 top oven grill ?

My oven has fused (a flash from the right side of the control panel) when the grill switch and the top oven switch were turned on at the same time. Resetting the house mains fuse now shows everything working except the solar grill. Checking the 4 grill tubes seems to indicate they are in order - they get warm when switched on but don't illuminate. What replacement part will be required?