Why does the amplifier left speaker go right and the right go left?

and maintain compliance with safety regulations.

There you have it folks. The UK nannies strike again. Because they know so much about product safety.

I don't find this to be an issue in the least.  Assuming the owner/user can read, it should be easy to set up correctly.

The issue of rear panel layout probably doesn't get the attention it should.  For myself a big bugaboo is the placement of the power cord inlet.  It really should be as far away as possible from both low level input/outputs and loudspeaker cable outputs, but that's not always the case.  The worst situation tends to be where the inlet is placed between the left and right channel I/Os.  It makes it very difficult to not cross power cables with signal carrying cables.

Why is the industry locked into the rear panel paradigm?  If a component is in the shape of a box (and that's a whole other paradigm), then there are six sides where connections could be placed.  In the language of the audiophile separating the power cables from the signal cables would result in a profound sonic improvement easily equal to a major component upgrade.

Actually, somewhere during the 50+ years I’ve been into high-end audio,, I do recall seeing at least a couple of components that have similar panel layouts, and I’m pretty sure that, when shopping for an integrated earlier this year, I found a couple of current models.

If cited correctly in this thread, the rationales for this reversal don’t seem to hold up to scrutiny. If the configuration was a way to avoid induced noise from internal components, relocating the power signal path would have resolved the problem. Apparently, Naim, like me, didn’t consider this aspect of the panel layout important enough to warrant a circuit redesign. And frankly, if Naim uses "custom" connectors, I’d expect that to outweigh such a trivial panel-layout inconvenience by a wide margin. If one can deal with the former, why would the latter be a problem?

My attitutde is along the lines of “That’s certainly worth pointing out, but bottom line, it doesn’t matter enough to warrant an entire conversation.” If you neatly route tie-wrap your cables to a rack, there’s no criss-crossing. If an amp is unracked & physically located between the speakers, it’s trivial, as one poster suggested, to merely reverse the input channels if crossing one’s pricey, uber-insulated speaker cables is a matter of concern, and otherwise unavoidable. Or whatever. IAC, it should be SOP to follow up every system modification with test content that reveals things like swapped channels, out-of-phase channels, etc.

FWIW, I’m hardly perfect myself in this regard: I got surprised by an analogous layout issue a few months ago. A new amp, just in from Germany, had outputs for two sets of speakers, but the A outputs were in a lower row BELOW the B outputs. When I first turned the thing on, there was no output b/c I hadn’t realized that I’d enabled the A outs but connected speakers to the upper row of B jacks. Oh my – I’d just assumed… But you know what they say about assumptions.

Having said all this, I want to thank the OP for pointing this out for the sake of other Naim owners. A worthy rule of thumb is: When you buy ANY European product, it’s always a good idea to RTFM first.

Pentaconn connectors, anyone?

Open the cover change the wiring to also put stickers outside. or Get it done by repairer just a soldering job.

What Nait is stating is nonsense. Look at a picture of the Supernait 3’s interior. There is plenty of room around and behind the binding posts. But notice the wires from the output transistors to the binding posts: they are straight with crisp angles, equally spaced. In order to wire the output normally, the wires would have to cross, ruining the symmetry. That’s the reason. My guess is Nait spent a lot of time developing that circuit board and when it came time to put it all together they noticed how the wires wouldn’t run neatly and had to cross. So it was a choice of either redesigning the board by switching around the output transistors... or change the stenciling on the back panel.