Being a qualified electrician myself, I wouldn't be connecting my ev car charger to a standard outdoor electrical socket; is is not one of the methods suggested in Section 722.I can see where the earth is bonded to the incoming mains supply and the copper pipe work a couple of feet to the external metal tap hence my puzzlement.
Regarding The other comments, yes my qualified electrical engineer has explained all the relevant regulations and is comfortable that what I’m planning is not in breach of the regs or dangerous.
I don't know how your electrical engineer has come to this conclusion. I'm not trying to make a thing of this, but the use of Class 1 devices, i.e. your car, outside the equipotential zone can be potentially dangerous, as shown in those videos I linked.
It is normal to bond any extraneous metal work; your tape may or may not be extraneous. It should be tested to clarify its status. In years gone by, it was normal practise to bond everything that was metal, such as radiators, metal windows etc. Thankfully, that is no longer the case.