I would expect £450-ish for Tesla charger. If getting an OLEV approved charger than I would expect the charger to cost £550+ and the grant to be £500, thus the charger to "cost" £50 ... rather than to be free. That seems to be either profiteering, or something for dealing with the Red Tape. Either way its £400 cheaper than Tesla / non-OLEV charger.
More expensive OELV-approved chargers are available, some with fancy capabilities - e.g. divert excess Solar PV into the car, or more aesthetically pleasing on a Front Wall - e.g. retractable cable.
Basic installation (wall charger location is within a short-ish distance of Distribution Board, or similar "straightforward" install) I would expect to be £500. Might get it cheaper, but should only be significantly more expensive if long wiring run, dig up the drive, have to run new, fatter, cable to garage and also fit a new sub-board in Garage etc.
So straightforward via OLEV around £50 for charger + £500 for install
£1,000 for OLEV charger and install, unless the install is complicated for some reason, looks expensive to me.