OK, first things first, I've fixed the windows at the front so they close. Partly to keep out burglars, partly to save some energy. The problem is that the plastic window plates that the window latches fit into have all broken. As a result the previous owners had used draughtproofing tape like sellotape to keep the windows closed and the draughts out (!). Didn't work very well, and not very good at keeping burglars out - most of the ground floor windows could just be opened from the outside using fingertip pressure.

I guess this is a problem with quite a lot of aging double glazed windows, and we had a bit of a think about what to do to fix the problem. In the end we've made (with many thanks to my dad for his brazing skills) 12 replacement catches which have been pop-riveted into the original holes. The windows now seal with a satisfying pull in to the integral draughtproofing strip. Result.

How much will it save? Watch this space.