Back again! I had a little rethink. When we bought the kitchen we were never too accurate on the total distance the pantry made it very difficult to measure up so we factored generous finger spaces for the washing machine and dishwasher and accepted we would have quite generous trimmers at each end of the cupboard run. However paring everything down to the minimum we can now squeeze in a wine rack this would now allow me to fit the socket behind the wine rack which if it does go the full depth I can easily reduce to allow hand space. So the socket can go the other side of the trunking.

As for standing the CU off the wall I thought that had gone by the way with all the focus on maintaining the flame proof integrity of the CU. that makes things an awful lot easier. As the trunking already fitted is below plaster level I will not take it behind the CU but will stand off the CU enough to ease the cables behind. It would be difficult to align trunking with the knock outs as having to come in from the side two of the fixing screws are below the level of the knockouts. I presume that the stand offs need to be fireproof and not like the two wooden battens the present CU is fastened too. I take it from what you said it would still be OK to flood the area of the rear entries with intumescent sealant to maintain integrity.

So it is looking like I am going back to Plan A bring the tails up through the LH knockout, I will leave generous space to fit the socket to the RH side if I have to and just live with the tails being bent round to make space.. In the long term it may not be so much of an issue as we will be getting a smart meter fitted and from the ones I've seen they are quite compact and if needs be can be fixed lower down than the present meter is on the DNOs board.

One helpful factor is because I am not fitting the meter tails direct to the CU but to the isolator. I can actually makeup the tails between CU and isolator when I am arranging the MCBs, Main Switch and RCBOs etc. So I can fit them in before hanging the CU on the wall as they will simply fit into the other end of the isolator.

Please confirm this is a workable solution.

Richard