Re: EV GSM and metering?
Anyway, if HMG start charging me an extra energy tax to charge my EV at home,
Not the preferred model. Government have already looked at and (in effect) chosen road pricing as their future model, although they're not sure how they will actually do it. I expect it'll be GPS real time tracking, possibly using the e-call capability (you remember they said there wouldn't be any scope creep? Not that anybody believed them). Because GPS isn't always that accurate they might struggle with road specific charges, though time of use would be easy. Busy or trunk roads might see higher pricing by using ANPR in parallel with the GPS tracking. Additional great benefits for government include charging you more when it suits them, a vast database of everybody's movements, the ability to issue speeding and parking tickets automatically.
But regardless of that, your EV charging costs will at least double anyway, for two reasons - first the continuing "climate change panic" changes to the energy systems, and all the subsidy fuelled PV, wind, and network changes, that's putting up your charges every year for the next decade as a minimium, and second because with the emergence of EV charging demand and static battery storage for peak loads, the idea of really cheap off peak electricity is doomed, because as off peak demand rises significantly, so will overnight power prices.