Thanks to everyone who contributed to this, especially @mattjmiddleton for the pain-free screenshots of how to get it all set up. I think CoRE might have updated and changed one or two things but I figured it out (or perhaps I followed it wrong - where the instructions said “if hue dimmer is pressed, select blah blah” I couldn’t just say “if hue is pressed”, I had to say “if hue buttons 1, 2, 3 or 4 are pressed…” but that’s a minor thing.
Not yet set up any held states, I just wanted a switch for the bedroom light that can live on the wall behind the bed that either of us can operate.
So now for £19.99 I’ve got a four button switch that I bought off the shelf in the UK, rather than £30+ mail order or £20 sent from China in just 60 days…
For anyone reading this doing the same thing as me - if you buy a dimmer standalone, then follow the instructions to pair it carefully. You need to hold a button, search for it, name it, then reset the dimmer with a pin, and search again (don’t remove it from ST, so it won’t find anything, but the light will stop flashing).
I didn’t do this as I thought I knew better - WRONG. The button presses aren’t detected until the second search.