[PaulR]

As Mike says the elements look good. They tend to get distorted and have a distinctive burnt patch on one area when they burn out. The thermostats that control them do fail though. You could test for a voltage at the element terminals or swap the thermostats between two of the rings and see whether the fault remains on the same ring or moves to a previously working ring.

We had a slightly later Belling cooker, dating from the mid '60s and within a couple of years the heat resistant insulation on the leads that led to one of the rings cracked and shorted to the case blowing the thermostat.

I doubt that oven or grill elements named specifically for that model will be available but if you take measurements of them you may find that they were fitted to later models or completely different cookers. Regular searches of ebay may turn something up.