I worked out the Octopus off peak tariff was not going to save me money. Unless you charge from empty to full every day with a PHEV it costs more in general electric charges than you save by charging cheap and it assumes you only want to charge at night. Whenever I come home in the car I plug it in to top up the battery until the next time I go out, so it’s always charged when I want to use it. On a 3 pin plug it might take an hour or 3 hours to charge back up. I rarely run the battery out on any one trip.
Oh and on the Volvo, a home charger would reduce a full charge from 4.5 hours to 3 hours.
You have to do your maths, but having a 3 pin socket fitted (if you haven’t got one) £50-100, a home charger £800-£1000. Depends how many miles you do every day, but the extra cost of a charge point buys a lot of petrol for the times your battery runs out.