Spotted these the other day at PB Tech - seems to be the holy grail of an in-wall switch/dimmer mech that is actually compatible with standard NZ light switch plates, looks easy to wire and actually shows the status of the circuit. Stupidly expensive tho considering kit that does the same thing but in different a form factor goes for < $40...

Dimmer: https://www.pbtech.co.nz/product/ADPBRS20967/Brilliant-Smart-Smart-Dimmer-Mech---WIFI-Trailing

Relay: https://brilliantlighting.com.au/product/smart-wifi-relay-mech-7a411a (can't seem to find this anymore at PB Tech, it was on their site a while ago...)