They have to be installed in compliance with the Electricity at Work Regulations.
Domestic or not.
With “contracts” like those on offer here the OP seems to want a fixed price for the job regardless of location & condition of the existing installation.
Following BS 7671 in full is a HSE recognised method for compliance with EAWR.
This is supplemented with the IET guidance which includes the CoP for vehicle charging installations.
The crux is that because the DNO's are allowed to breach ESQCR so they can mximise profit for their foriegn owners to syphon off via tax loopholes to their own countries to bolster their profit there and subsidise their home countries network at the expense of the UK, a vehicle charging point must be TT, basically.
No allowance for things like asbestos being found during the works, it has to be done as cheap as possible with no regard to safety.
The thing is the installer is the one HSE will target if there is a death.
An issue often overlooked is that the charger is in the vehicle & the mains earth is common to the vehicle body.
Thus failure of the CNE conductor in the distribution network could be fatalif the supply to the point is TN.
Also,
So the cost for ensuring that the job is safe is passed back to the householder/installer, to allow for the failings of the multi £M profit making DNO.