TLDR: is a Neutral wire in a "live + neutral + ground" setup the load output wire or a neutral wire when doing light switches?
My house is ca. 1907 for context, and the only wires I've got are:
- Red (Live), tested with multimeter.
- Grey (Neutral..?), was connected to common terminal of old (traditional) switch
- Exposed (Ground?) Connected to terminal housing.

My new dimmer supports "with or without neutral" circuits:

but what confuses me is how the 2nd wire is a neutral line, but clearly is being used as common; should this be connected as neutral, or do I have a "no neutral" circuit setup?
I've got some old wiring from the cellar to demonstrate what I think is correct, including some ground wire taped up to connect the L+N terminals as the circuit describes:
(NB: Brown is Live, Blue is Neutral, this wire postdates the house by a LOT)
Yeah the house is an ex rental so the wiring will have been redone to meet regular council inspections, so it's more modern than that! Useful diagram btw.
Good to know I'm not crazy thinking that it's DEFINITELY a neutral wire. I think the UK's terminology is a bit of an arse because in switch circuits the neutral appears to be called a "common".. i think
In the end, I did just do as the pic showed but with clips to combine the live terminals. Annoyingly it both made a shite connection and the lack of load on neutral made it flicker a bit so it's back to the flicker switch for now.
I'll come back to it when I've got those hits sorted :) ty!