Chaps, do you all sriously think the UK will have rolling blackouts this winter? It's just not going to happen, youre all worrying about nothing.
Here's a summary of why V2L is not the panacea you may think it is/will be from both personal experiance and research:
I've never managed to use the V2L on our ZS without the car being powered on, which means someone has to stay with the vehicle at all times (yes, I know some seem to have had success with being able to lock the car, but that just plain doesn't work for ours), so that alone makes it very unsuitable for much other than charging up things like e-bikes and scooters if we're out and about with those too (because I don't generally travel with a coffee machine, kettle or portable heater).
The lack of earthing (amoungst other things) makes V2L exceptionally unsuitable for powering the majority of appliances one would wish to power in a power-cut anyhow (people have discussed fridges, boilers etc.).
There is no way to properly connect it to your home, and certainly no way to automatically stop your house overloading the car's battery in the event it was drawing too much power. The phase mis-match, if it didn't break some or all of your electrical appliances would probably also be noticed by the power company and bring some unwanted attention to your door.
Buying a car because it has V2L, which is still basically just a gimmick seems somewhat of a strange decision to me, buy the car you want, enjoy it and if you really feel you need protection from power-outs, but a decent battery backup (they are VAT free at the moment in the UK) and charge that on your overnight rate.