10C is a great indoor temperature if you want condensation everywhere and eventually mold, but that's a price worth paying to not be considered "wimpy" I suppose? https://www.homebuilding.co.uk/advice/minimum-house-temperat...
That article and the supposed experts are idiotic. Condensation is a function of relative temperatures and humidities. If your house is warmer than outdoors, then you're not going to get condensation from outdoor air.
At 70% RH and 15C air temperatures, the dew point is 10C - which could easily be achieved along the exterior walls of an older more poorly insulated house.
My house is bone dry in winter with the windows regularly open. The humidity concern is idiotic.