We took an opportunity presented at Clapham's Energy Day, organised by the Clapham Sustainablity group, to have our house checked with a thermal imaging camera.
The images have a temperature scale at their base (the air temperature at ground level was 10.5°C), so on the left, which shows the roof above the two B&B bedrooms, shows a roof surface temperature of around 5°C - well insulated & nice & cosy!
The photo on the right shows the road side of the roof & the stairs window. Despite showing red walls, the temperature scale still shows that this was at or below air temperature.
The temperature in the top left corner is that of the spot in the middle of the image.