The problem is at least partly because people in the UK are enamoured with old houses to the point of detriment when it comes to things like thermal efficiency.

The problem is at least partly because people in the UK are enamoured with old houses to the point of detriment when it comes to things like thermal efficiency. There are all sorts of heritage laws, local "conservation areas" etc that forbid things like double glazing, modern insulation, etc. The quality of the typical housing stock here is very poor.