Guessing why another electrician has done something will leaving you in whirlwind of three things: was it done with some logic, was it pure laziness, or ignorance to what should have been done, if we give the original installer the benefit of the doubt, their logic could have been, they did not want to use an insulating gland as this would make the gland its self an exposed conductive at the EV charger with the SWA connected to the buildings main earthing system. a problem if the supply earth is PME I am assuming it is based on the use of a OPEN device. 

Meaning in the event of a OPEN fault the charger would be isolated but the gland could still be an accessible earth path from the MET and true earth posing a significant shock risk to anyone that came in Contact with the gland for example any one investigating why the charge point is not working in a PEN fault.

If this was their logic the use of the dome top gland isn't a bad idea but it isn't the right idea.

My opinion would be to use a CW gland at the EV charge point and the insulating gland at the OPEN device this way in normal working circumstances every thing is earthed via the main incoming earth, then in the event a OPEN fault the supply to the EV charger is isolated including the SWA and CW gland as this is now connected to the load side of the OPEN device.

George Hancock said:

My opinion would be to use a CW gland at the EV charge point and the insulating gland at the OPEN device this way in normal working circumstances every thing is earthed via the main incoming earth, then in the event a OPEN fault the supply to the EV charger is isolated including the SWA and CW gland as this is now connected to the load side of the OPEN device.

But in many cases the O-PEN device (or RCD if it's being TTd) is integral to the charge point....

   - Andy.

George Hancock said:

My opinion would be to use a CW gland at the EV charge point and the insulating gland at the OPEN device this way in normal working circumstances every thing is earthed via the main incoming earth, then in the event a OPEN fault the supply to the EV charger is isolated including the SWA and CW gland as this is now connected to the load side of the OPEN device.

But in many cases the O-PEN device (or RCD if it's being TTd) is integral to the charge point....

   - Andy.

Hi Andy 

This is true, then other design considerations would need to be made, as this would be outside of the scope of the original question where the charge points are connected to a separate OPEN device in a TN System.