I have told the customer that this a longshot due to the age of the appliance and the complete absence of any sort of model number or even rating plate.
The hob is a non-standard size, fitting into a hole 730mm x 480mm; the rear two rings are ceramic pots; the front two are halogen pots. One of the halogen controllers has failed. This is 7 position selector switch (6 heat and 1 off), comprising a ceramic block in a metal cage. There are six terminals along one side of the ceramic block and seven along the other. Also a suitable sealing grommet would be nice.
Sorry to waste everybodys time, but hopefully somebody’s memory will be jogged!
Regards,
Penguin.