Motability fitted an OHME charger for me, which is 7.2 kWh.
I am fortunate that I haven’t experienced any range issues – maybe because I got my car end of July when it was warm – also I don’t do a high mileage.
If I did have issues with range dropping over the winter period I would certainly run the battery down and 3 pin charge to try and improve the conditioning of the battery. There does seem to be evidence to suggest this does work – but either way I would loose nothing by trying.
I know you said Struth that you collected your car in winter and it took a while to improve the conditioning.