@1bigwink - I’ve just bought one of these battery operated z-wave switches to test and a single paddle face plate for it - apparently they work with ST - I’ll report back when it arrives.
http://www.vesternet.com/z-wave-me-wall-controller-set-with-frame
Here’s a community project that lets them work as dimmers etc - [Release] Z-Wave.me, Popp, & Devolo Wireless wall Controller & Key Fob (EU), with button controller dimming apps and CoRE integration
I’ve also designed prototypes for a cover to attach to a uk light switch using magnets to mount a switch like this on top of a normal light switch, and for a frame so you can use any standard 1 gang blanking plate to do the same thing. I’ve ordered 3D printed prototypes and am thinking of running a Kickstarter to get them produced by injection moulding.
The thread for them can be found here - Design for a frame & cover to let you "replace" a light switch with no changes to electrical wiring needed