Wireless thermostat cable type

I have a Viessmann vitodens 100-w 30kw being controlled by a EPH CombiPack4 wireless thermostat. I need to move the receiver because it is struggling to communicate with the thermostat in the location I want to put it.

Could someone advise on the cable required please? I can see that it's 4 core but just wondering whether 0.5mm2 is sufficient or if I would need something more substantial?

0.75

0.5 is ok as its CCC is over 10 amps and most boilers are fused at 3A