I run the hifi from a radial circuit (ring mains circuits are illegal here) with just the one socket. The cable in the wall runs more than 1m away from any other cable once it leaves the box and is standard regulation 2.5mm2 solid core, the socket a decent quality (but not hifi blessed) one from Legrand.
A long time ago (before wifi etc) I tried the dedicated mains circuit against an ordinary one with 5-8 sockets - the dedicated circuit was a little quieter.
After measuring the mains over 24+ hours with a computer assisted tool, I installed an Isotek Syncro to deal with DC offset (this cured some nasty transformer buzz in the Nap250 I had at the time) and an ex-dem Isotek Sigmas (for peace of mind during electrical storms and a more even performance over the entire day).
Until I moved on to equipment with much more resolution than my Naim 72+HC+250 I could hear only very minor differences between mains cables.
With your Naim stuff, personally, I would go no further than a decent stranded (i.e. rack-friendly) shielded design like Supra Lorad.
With the current Aesthetix and dCS setup I am slowly trawling the 2nd hand market for Nordost Frey mains cables. They are much more to my liking than Cardas Golden Reference, for example.
I shall now don the tin hat and run for the fallout shelter