Michael makes several good points, and there is no challenging his command of detail on actual planning application in the area.
In particular, it is quite reasonable for him earlier on this thread to
prefer the option of developing brownfield sites (and some green field) around London which are not in use.
Are any of those active in local assemblies and civic societies prepared to contemplate the higher housing densities the wider public needs?
Of course they are, always just outside their area, which currently has the perfect density. (I jest of course).
Every area is different. My understanding is that the Sydenham Society were particularly in favour of Bell Green having significant residential development, rather than out of town style retail park. The Greyhound site is another good example of high density development in a site with high PTAL rating. Brockley will show other examples of this happening. Not quite high rise, but 5 or 6 storeys becoming fairly normal for such locations.
Anyway, I've tried to explain the point of view from people who I know were in that workshop. I hope that most people will see that their concerns are valid in certain contexts. A necessary force against those who would like to see South London turned into Nothing but Towers.