Trying to work out the best solution to control my UFH system.5 zones. New Combi calor gas boiler. Well insulated house with triple glazing. It's a holiday home so only occupied some weekends at present. I don't want to leave the heating on 24/7 for that reason. No internet connection. Looking at remotely controlled thermostat - perhaps a 'climote' I'd like to have control over all the zones e.g. bedroom temperatures lower etc. Any suggestions?

Are these new thermostats able to control different zones temperatures independently? I'm trying to work out how they work...I don't always believe what it says on the tin.

Is there 3G coverage?

You could control an internet based system via a router with a 3g dongle attached, or a really cheap phone (or 3G tablet) permanently plugged in creating a hotspot. Loads of IoT stuff for a Raspberry Pi if you are so inclined. Data usage, if you just use SSH or any inbuilt system will be pretty small. You could simply use this to just switch the system on/off. These guys do cheap data only SIMs https://mobi-data.com/#pricing

I'd be inclined to keep it simple and use the floor temp to largely control the temperature of the room. You say a combi boiler but does that drive the UFH directly or via a heat store?

I have a Heatmiser wireless system but room temp is largely controlled by floor temp. However, I don't like closed systems and I'd rather get something that can be accessed by different systems. I have not found the ideal one yet though :)