MrBen dear heart, it is a generalisation as I stated, but equally not s million miles from the truth. Yes socio-demographic change is a constant but not an irrelevant Darwin style natural selection process either. It involves real people and it's happening at a ridiculously and ever faster pace, and IMO for the wrong reasons. Looking back at previous waves of social change brought about by immigration and the industrial revolution, we see cities like London taking many decades to gradually change and for reasons primarily associated with work (initially at least). The more recent changes are often characterised by sharp house price rises which have allowed the natural process of the resident population to reach retirement age and sell up for a pile in the sticks (this is not uncommon historically), to become a savage opportunity for transient cash buyers from wealthier places to move in and make a bomb on run down property stock, turning these into million pound homes and forcing people out into the poorer suburbs and new towns to find anything resembling a half affordable property. Louisa.