As you say Phil, whatever about the legislation, I'd love to hear what the PVC companies are saying - their spin on things. What I'd give to be a fly on the wall in a 'non-obligation consultation'. Perhaps people here have had first-hand experience of them...
But as for the owners themselves, there's numerous reasons why windows are taken out.
A lot, if not most people, don't view their house in an architectural way - they just percieve it as home and don't look at it objectively, certainly not architecturally.
Maybe the 'rotton old windows' have been there since they moved in, drafty, bottom rail rotting, difficult to maintain, the sashes stick or are jammed, and they rattle in the wind.
All of these problems that they may have, combined with a complete ignorance of their architectural merits, just results in people not giving a second throught to their disposal.
A lot of people like the fact that their house is 'old' but that's about it - they don't mind if there's no period features at all - or at least they look for interior features but utterly ignore the windows - indeed most people probably go into standard red brick terraced houses when house-hunting and think - "oh great, the windows have been 'done' '".
At this stage in Ireland, 'having the windows done' is just as common a topic of conversation now as house prices and traffic all the rest of it.
PVC ompanies are the real ones to blame in this - every single one knows exactly what they are doing when ripping out sashes - every one of them, yet couldn't give two hoots.
I'd love to see them imbue their mission statements with the ethics of conservation as much as they wave about their ISO9000s in your face