OK I checked out those two sites and think this might be a good idea. I couldnt find any prices but its possible to internaly insulate 1 room at a time this way and therfore not break your budget. I would definatly start with the living room.

A standard British cavity, for buildings 20 years old will have been insulated. Old building possibly not but as long as the cavity is sealed well you wont have problems. If you have problems you would already see the damp on your internal walls. I only ever worked on one job in South London where the walls were constructed for thermal efficiency. They were 200mm thick compared to the standard 60mm.

I'm living in Holland myself but dont have a good grasp of the language yet so its difficult to follow whats happening. I know that recently they began a big project up in Amsterdam to double glaze thousands of council homes.

My personal situation is not so good. I live on a houseboat constructed entirely of wood except the metal hull. An average wall is 30mm wood/60mm insulation/20mm wood. The roofs are flat and of the same thickness and all the windows are single panes. My propane gas bill for heating was astronomical this last winter even with an efficient wood burner in the living room. My only advantage is I can collect a lot of free wood from along the canal. I guess this year I'm going to need a lot more :/