The utility companies wouldn't be pushing smart meters if there wasn't something in it for them.
Unless you have an uprated outlet (say 32 amp) and it was on a separate circuit breaker,
I don't think even the smartest meter would know what you were using the power for.
Having said that, you make a good point in that there will be a massive loss of income for HMG if no-one is paying fuel duty and the VAT on it
More about that here
Treasury will need to plug gap in tax as drivers switch to electric cars | Politics | The Guardian
Road pricing would appear to be the most likely solution
Cheers
Bruce