I’m not sure how securely it would fit in the ND cup holder because they are largely open sided and the type of base you are looking at usually has expanding fins which require a solid “tube” all the way round. You could always find a suitable vessel to fit inside the cup holder in which you could place the phone mount base but the inside of the holder is narrower at the bottom than the top so might require some packing. Another concern is that the cup holder mounts are not completely solid and there is some movement. This would translate to even more movement at the phone end which might be annoying when driving. I have been looking into this as well because my phone overheats just in front of the gear lever in hot sunny weather. It also depends if you need to see your screen when driving or you have Apple/Android car play (in which case it’s not necessary).
I used to use one of these (might have been a slightly earlier version - I’d have to dig it out from my garage to check): Phone Holder, MX5 Mk4 RHD – MX5 Parts It worked well but did rattle sometimes so needed tightening up. Now I have CarPlay I don’t need to see my phone screen so I don’t bother any more.
My phone won’t stay put in that space in front of the gear lever.
I had a phone holder that I used in the minis I owned and that fitted directly into the cup holder and you screwed the base out to fit the holder, the actual phone holder was directly above the base not on an extension like yours, it worked really well although you had to look down if you were using it as a satnav. I dug it out a couple of months ago and tried it in the ND and it was terrible, the cup holders are just not stable enough, it was wobbling all over the place.
It’s available for RHD cars and slots into the cupholder bracket on the passenger side. Plugs into the “hidden” socket and is magsafe compatible so it holds and charges an iPhone while in its case. The only problem is that I don’t have an easily accessible drink any more. I imported mine from the US but I think it is available from the UK now. The charger base is on a ball and socket so very adjustable.
I got one very similar (but much more expensive) from mx5things
It works very well and I plug it in to the “hidden” 12v socket so very neat. The main issue is I can’t use the cupholder there now which is a pain on longer journeys and the phone is too low to use as a satnav easily.
I retrofitted wireless CarPlay (2018 ND1) so the phone satnav and Tidal are on the main nav screen with the touch screen enabled when moving
So now I don’t bother with it for short journeys and for longer journeys I’m in too minds about rather having a convenient cup of coffee and plugging the phone in.