Finally, everyone using "lol UK and Nintendo" as a security blanket need to think back to just how successful the Wii was here. It was a phenomenon. It's fair to say that Nintendo absolute dominated that era of gaming, it's only since the disaster Wii U that people came up with this idea that Nintendo is fundamentally weak here.
The Switch has been very successful IMO, it just isn't the Wii like success that got those 20m+ per year sales and pulled in huge numbers in the UK.
The UK is a market like any other if they aren't doing what they need to here then it will be true elsewhere.
Not quite joining in the pile-on, but on a specific point:
Anyone familiar with the UK games market and Nintendo's place in it - for generations now - would tell you that they have had difficulties here since the N64.
In fact, I think there's an argument to be made that only the SNES and the Wii could be said to have been truly successful Nintendo home consoles here - the NES didn't get a real foothold, arguably due in large part to the success of the home computer here (Spectrum, C64, then ST and Amiga), the N64 was middling, GameCube was a flop, and Wii U was a catastrophe (and one that, coupled with the tepid take-off of the 3DS, did a lot to kill off/drastically reduce Nintendo's presence in general retail).
Sega - with the Master System and Megadrive - did good business here alongside the SNES, then Sony came in with the PlayStation and dominated against the N64 and Saturn. The PS2 was similarly dominant against Dreamcast, Xbox and GameCube, and it was only with the 360 and Wii, and the misstep of the PS3, that that position shifted. The PS4 felt very much like a return to the UK status quo since the mid-'90s - Sony on top, other platforms duking it out for second.
I think it's entirely fair to say that historically - for reasons of timing, gaming culture, platform-holder mistakes etc. - the UK is not a great market for Nintendo, and pointing to the Wii while ignoring the decades of struggle in the home console market seems a bit silly.