On 10/03/2020 16:01, Harry Bloomfield wrote:
Brian Reay wrote on 10/03/2020 :
One of our previous houses had been extended like that. Fortunately,
there was a crawl space, accessible via a hatch in the garage, and I
was able to gain access. I lined it with foil and insulation. It made
quite a difference.

If there is a similar space, it may be worth making an access
somewhere is can't be seen.

He says not, but it might be worth his making some access to add
insulation.

It's not an extension, it is the originally built. I'm surprised that in
the 1960's this was an acceptable way to build homes. He says his was
one of the first, later ones of the same design had to have insulation
added.

Perhaps extension was incorrect, more like modified in the 60s style.
The upper floor, which is of interest here, was changed, as was the
(1930s) ground floor. When finished, it looked 1960s.