When I talked to the guy that fitted ours on Monday, he said the charger costs about £400-500 and the rest (typically about a £1K in total installed) is the labour but since OVO have a deal with Ohme and Mobility he believes the cost to mobility (and also NHS workers too via their scheme) is a lot less. must say I would expect that a large customer like mobility would get a large discount as the installer said he is always busy and does a lot of mobility customers. some he says have now got two chargers, one house hes been fitting at had 3! , he himself has two, one for the works van and one for his wifes EV. Apparently if you have more than one charging at a time they can back off the charge rates to keep the loading ok on the network cables.
not sure if mobility would fit a second charger if you already have one installed off scheme , that said they didnt ask if i had one already when we ordered the EV , just asked if we wanted a charger installed. you may have a problem with a second charger if you DNO company is worried about loading on you system but other than that i would expect that mobility would just install you a charger if you wanted one. if you ordered a second ev 3 years later i dont know what they would do then ?