SONOFF Orb-MW1 wiring question for UK light switch

I’d like to install a smart light switch (I am in the UK), and am looking at the SONOFF Orb-MW1. I have zero knowledge of electrical/lighting circuits, and was looking for guidance on (a) whether that Sonoff switch will work on my switch wiring, and (b) whether it’s a job that I can take on myself.

The light switch in question is in the hall. It is a single gang switch, but the light that it controls can also be operated using the 3-gang switch on the first floor. This is how the hall switch is currently wired:


Can anyone advice on whether the SONOFF Orb-MW1 can be connected to this wiring and work correctly, and if so how I can identify which terminals to connect each of the three cable to? (2 red cables go into the base of the existing switch, and a grey cable into the top of the switch).
???

No, that Sonoff requires neutral wire, which you don’t have.
And it’s not compatible with the second switch on you wiring.

Thanks for confirming - that’s a shame.
Does anyone know of a smart light switch that will fit into this wiring setup and continue to support the existing 2 way switch setup, while providing continuous power to the smart switch module even when the physical switch is used to turn off the light?

Relay is more suitable for it like sonoff basic (R4 or the latest V5 with matter) where you simply install it on the light fixture without adding new cables

Shelly 1L Gen3 could be one option.

Thanks for the suggestions. Would those options lose power when someone turns off the wall switch? (which is the main thing that I’m trying to avoid)

If correctly installed, Shelly stays always powered on.