Currently planning/installing an automation system to control lights/audio etc, but I also want to control my central heating and need some advice please:-

I live in the UK and have oil central heating which heats the radiators and the water

I currently have a honeywell st6400c programmer which has 2 x 7 day timers - one for heating and one for water - I don't have a separate room thermostat, just thermostat valves on each radiator

I see from reading up that the honeywell st6400c fits to an "industry standard backplate" so can be easily replaced, but the question is replaced with what - can I get a direct replacement for this that supports z-wave or x10 or similar? it is now an obsolete model and honeywell website say a direct replacement would be the st9400 or s9420c (links below), one of which talks wireless to its own themostat but its how I link into my HA that is confusing me



Any suggestions please!!?

Thanks in advance