my advice would be to get the OLEV installers list:
www.gov.uk
find a small local installer and negotiate the best deal you can for a chargepoint that suits you ( they are all functionally very similar)
personally I would not bother with the Tesla ( unless you really really want the buttons which are cool to be fair) and I would definitely not go to a chargepoint manufacture which will probably be an overpriced install with a huge markup from the lowest bidding random contractor in your area.