Founded, not well-founded I think. I can't see the evidence of intent for what you allege. I can see stupid policy. I can see failure to deploy. But to suggest the intent is remote control or track and trace, demands a basis. Whats your reasoning beyond supposition?

Why don't they e.g. do this with the BMW ICE cars which carry a SIM card?

Remember its the deploying state we're talking about, not the specific risk of BYD being under control of the CCP. Your response implied all EV in the UK, are part of a plan to supervise/monitor use of EV cars, not the foreign actor risk as I understand it.