Control of "simple" fan based central heating

I have a radiator system to most of my upstairs. Each room has a TRV for temp. And the system is control via a timer only. At some point I’ll look at adding something like a z wave relay for controlling the system remotely.

I also have down stairs a bit of a fan assisted central heating that is controlled by a physical 4 way dial. Again it’s simple. No tie in with temp or anything.

If I could get remote control of this dial I could tie it into a temp based system.

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I’m thinking long term to go z wave. For a co troll such as this would it be the dimmer relay? And would I keep the physical switch?

Are there any other interim option?