Main Earthing Conductor

What? I would of thought that was DNOs responsibility what they are saying is its ok to work on the cutout  normally they don't let anybody touch there cutouts and fuses  they are normally very strict about this

There are some designs of service head where a terminal is available to connect a PME earth, and all that is needed is a flat bladed driver, there is no seal on that part.

(some common types shown here, see the variations....)

~If (only if) it is one of those and he has been told to proceed, then that is fine. However in his shoes I'd prefer a clear permission as an Email or text, not just the word of AN Other in a van.

The usual thing to do is to add a foot or so of 16mm and then screw one of these marshalling terminals to a convenient surface and bring gas and water bonds etc to it.

There are other designs of cut out that cannot be opened to get to the earth terminal without exposing live bits, that sort is always a DNO job, but you need to have the link wire to your own marshalling block dangling nearby ready and waiting if you want them to wire it in for you.

Mike.

Thanks Mike. I'll be doing it for him but I'll get confirmation from the DNO first and check it's as shown in the link you sent. Thanks for your help