I have a hob and double oven on a 32 amp MCB and 6.0 mm cable, I also have a data logger that doesn’t measure below 10 amps. When I tried the data logger out at home for a week it barely recorded anything and never got up to 32 amps. People seem to go to extremes either completely underestimating the true demand or completely over estimating it rather than judging it is as it is. Electric showers, car chargers, etc are fixed loads, they are what they are so you don’t need overload protection because the circuit should be designed to take the full load. Socket and cooker circuits are designed to take up to the rated capacity of the circuit, but can be overloaded by too many appliances being plugged in or excessive use far in excess of what is normally expected, so they need over load protection.
They said that's why you work where you do, I think they assumed you worked at screwfix I guess and not a qualified electrician.
None of us work for Screwfix. We all just volunteer our time to help others on this forum! There are a couple of Screwfix moderators, you will see Screwfix in their name.
I spoke to indesit also they said the oven can be run on 32amp and 6mm wire. They even said 30amp would be sufficient and I though I heard him say either 3 or 6mm but that last bit might be wrong.
Don't think it's down to experience or qualifications, some sparkies are just blinkered like when they see a plastic consumer unit and immediately say its illegal and must be removed
Experience will tell you that there are literally millions of cookers installed on 30 and 32 amp protective devices this in existing installations with 6.0 mm circuits. Training and qualifications means you know why.
BS7671:2018 The eighteenth edition of the Wiring Regulations. 311.1 For economic and reliable design of an installation within thermal limits and admissible voltage drop, the maximum demand shall be determined. In determining the maximum demand of an installation or part thereof, diversity may be taken into account.