wmsteele wrote:

Need some advice on a new property that I moved into this summer. With
winter now setting in and temperatures falling I have become
increasingly concerned with the buildings insulation / heating.

A fairly powerful 35kw combi has been installed. Radiators all perform
as expected with no cold spots on any of the panels. Thermostat
controls are in the main hall on the ground floor. Setting the
thermostat at a fairly reasonable 20c results in the boiler operating
constantly, never reaching the 20c setting.

Size of house?
35Kw should heat most houses quite warm.
I expect that in fact it's modulating down to some much lower power.

Simple test.
Turn it up to 35C.
What happens?