A very comprehensive summation Glos Guy.
Looking at it from a pence/mile basis, it must be remembered electricity to charge a PHEV isn’t free (except if you spend half your day in Tesco’s). I calculated for one car running on electric would cost 6.5 per mile (assumed daily charging from home) against 14p per mile using petrol. Estimating the proportion of miles in a year spent working within the battery’s range and outside of it gives some idea of the savings which might be made. If you can’t charge at home or at work a PHEV isn’t a practical proposition as most are very slow chargers.
On the positive side a PHEV gives quiet running on battery around town and with home charging, the car can be preconditioned – warmed up and windows defrosted in winter and cooled in summer before leaving the house. If you do a lot of daily short journeys that’s a real gain.