My sister has a 'Stoves' Aga type electric double oven and hob. Her  hob stopped working a couple of months ago, after working intermittently for weeks. The manufacturers tried to get her to buy a new one for a 'special reduced' price, saying that they couldn't repair it. She held her ground and eventually they gave in and miraculously found some parts and came and repaired it. Probably best if you contact the manufacturers to see what they offer.