We have had an Ultimate PHEV for 2 years now it is a great car. For short journeys we keep the car on electric and usually get approximately 30+ miles before it reverts to Hybrid mode. On longer journeys we plan when to use the electric power, we keep the car in Hybrid mode and change to electric when we are in Urban areas or stuck in traffic.
We use a granny charger all the time and when we got the car the cable was included but I think this has changed now. We were told by our dealer that the Granny charger is now referred to as an emergency cable and it is no longer supplied with the vehicle.