Anyone have a working setup for a Heatmiser "Smartstat"?

Hi there!
After an 8(?) year absence I’m back to give Home Assistant another go. Things are looking up for me!

Some thing I’m curious about is if anyone has a working setup for the Heatmiser Smartstat that i could pinch and perhaps ask a question or two if needed?

I remember getting viciously stuck with it last time and hoping I can get a step or two further this time :rofl:

The particular model is:

thank you in advance
Jeremy