You might want to take a look at theseswitches and the matching face plate.
I fitted a dimmer 2 into my light pendant (had to change it for a slightly bigger one) because I couldn't fit a Dimmer 2 in my wall socket even with a 10mm extender, didn't fancy channelling the boxes out as I did one before and it was a bloody nightmare (House built in the 60s).
Anyway they stay 'in' at the top position and when you push the bottom they spring back out.
This allows me to push once for on/off, double click for full brightness or hold for dim up/down.
They also do two button face plates and as they are grid you can mix and match with smart switches or not.
There's load of places that sell them that was just the first link that googled, the reference number is md004pw they also have loads of others like one that stays in the middle so that you can push the top or the bottom in and they spring back, bought one of those before I realised you would need another wire in the wall to carry the switch 2 command, doh!