If that’s the case there’s little point having a 3.6kw (16A) one fitted when you can get an external 13A plug fitted for a granny charger at 2.3kw (10A). To 7kW (32A) is going to cost £500? And it still comes back to many PHEVs will not charge faster than 3.7kw – Mini and Volvo for two.
Obviously if you go full EV on the scheme you get the charger for free.