Everyone tends to consider ones own set up when giving advice, in my house I have 14 RCBO's which is a MCB and RCD combined so the cooker has it's own RCD so I can be reasonably sure if it trips it is the cooker, but many houses don't have this, so some reason they group many circuits together on the same RCD, and so it is hard to be sure what is causing a RCD to trip.
There are two tools we use, the insulation tester which is used dead and puts 500 volt on the supply to see if leaking, or the clamp-on ammeter which measures the unbalance. Both are expensive cheapest around £40 the clamp on has to measure down to 0.01 amp which makes them expensive. And both need so skill to use.
So with some thing like a suspect kettle we find a socket powered from another RCD to test it, but the cooker is not easy to power from another supply. So if a single ring causes it to trip we would assume that ring is faulty, but if multi rings cause a trip you have two options, call some one to repair it so they have test equipment, or decide it is time for upgrade anyway.
There are basic 5 types of hob, the hot plate which you have, split into three types iron base or ceramic or mineral insulated ring but it is a simple heating element, slow to heat and cool and wastes energy, but we have used them for years and they work. Then the halogen hob, always ceramic, slightly faster to old heating element but not that much better. And finally the induction hob, where the hob does not get hot as such, it makes the pan heat up, pans need a base a magnet will stick to, they are far safer, much faster, more economic, always ceramic and if controlled by knobs so fast acting that like gas you don't need to lift a pan if milk starts to boil you simply switch off. Many have silly touch controls so although the hob can switch off fast, the human machine interface is too slow, yes HMI is technical name for knob or touch controls.
As full cooker you tend to get control knobs rather than touch controls, and also the ovens tend to use well over 3 kW so have closed door grilling and other functions not found with split level, we have stand alone, mother had split level, her oven said it had same functions as ours, but it used time share so no where near as good, but daughter in law has steam in her oven which we have not found in standard size stand alone.
I have only found one shop when we went to look that had demo models wired up, you are looking at around £600 to £1000 so really you do want to see one working. So your problem is if you think the cooker is faulty do you spend out having it tested and repaired, or do you up grade. If you can't afford new induction then get it repaired until you can afford one. You can buy a cooker for £160, but with induction it jumps to £520 (Currys price) so to upgrade is expensive. If one ring is faulty a repair man could simply disconnect one ring, so to get it going likely just the call out price. That depends where you live, living in Mid Wales I find tradesman are cheaper than when I lived in North Wales, not what I expected.
