Don't want to name names but my Ampera only charged at 3.6 kwh so I never noticed it until it was sold. I had asked for a 7 kw charger as I wanted to future proof. The guy I sold it to was an engineer and took it apart to check everything was ok and showed me the plate saying 3.6 kw - ended up having to give him a refund.Grant is unlikely to cover it all and I think it has been reduced since I put my first one in 3 years ago. All depends on the type of charger you buy which will dictate the price; also useful to negotiate as there were mainland companies who could (and would) do it for me cheaper than some local suppliers. Also make sure you are getting what you are paying for; I was told I was getting a 7kw charger but found out later that it was only 3.6kwh.
I have a Zappi 2 and whilst it is expensive it is a really good smart charger. Lots of different settings and can be controlled via your phone with wireless updates; they also have a forum if there are any problems. I found the back up from myenergi really good too as VW's can be a bit funny about delayed charging and they sorted it out.The most recent one a friend fitted, the unit itself was around £500. Although by sounds of things it was not very easy to use. Customer bought it from a local supplier. Project EV was the brand.
From what he showed me of it....it looked kinda cheap, although does seem to comply with most of the regs easy enough.
The Zappi V2 does seem to be one of the better ones from a lot of the youtube videos.
Certainly the Tesla charger is a bit crap