Despite my slightly flippant note the other day, personally I'd not blink at re-doing the clamp one to get all the strands under the jaws, or using a suitable lug or pin  crimp if upgrading to a larger gauge of earth cable that was not an easy fit.

pin crimp idea for fat wires into thin terminals - other designs are available...

The flat band one I'd be a bit more cautious with - I suppose it may be official, especially if it is tinned copper, but, well 'yuk'. I think if you are obliged to work on it, then you are right to seek DNO advice.

If the DNO do decide it is worth coming to look at it, could you let us know what they say, please, for future reference as it were.

Mike

Thank you for the pin-crimp advice, I have passed it on to the electrician involved. I am hoping to visit the same area next week and see if any other properties have the same type of connection. I suspect I will find a few more which should hopefully help me in dealing with the DNO. I will post their response.

Thank you for the pin-crimp advice, I have passed it on to the electrician involved. I am hoping to visit the same area next week and see if any other properties have the same type of connection. I suspect I will find a few more which should hopefully help me in dealing with the DNO. I will post their response.