My review could have been five stars, as from start to finish, I have been happy with the product and the service, however, I feel there is room for improvement.
After I had the system installed, I was struggling to get the best out of it and avoid sending power back to the grid for little or no reward. I have batteries, which help with this but a neighbour told me about a device called I boost!
This unit diverts any power going back to the grid to the hot water immersion heater. This has increased the efficiency of the system and has saved on heating oil costs. I would recommend that this should be offered as an installation option.