Round our way we have some areas which use very old cabling originally put in when the network was DC, the joints can't withstand the high fault currentsyou get with pme.
I had a very similar job to the picture in the op. Three cottages built for the gasometer staff, no 1 was tt, no 2 homemade pme and no 3 pme from the cutout with a SWEB laminate stating pme. I was in number 2 and had poor efli so called the DNO who attended very quickly and referred this to a network planner who said I must tt it. When I showed him the laminate in no 3 he agreed that it was their issue and the 3 cottages needed to be resupplied. Some weeks later I was asked to be in attendance as the contractors had done the excavations and they were going to bring in the new supplies. The old school jointer allowed me to watch as he opened up the lead encapsulated joint, disconnected the old feeds and then used one of the new (idiot proof!) joints for the replacement supplies, the whole time he was giving me a comentary on what he was doing and explained why the old joints were not suitable for the pme fault currents. I found it fascinating and was impressed to watch a skilled jointer undertake his task
