Tim,
It is hardly as if Forest Hill is immune from, or should be immune from, residential developments. Along the railway line Forest Hill has found plenty of space for higher density developments in former brownfield sites. Phoenix Works, Clyde Terrace, City Walk, Normanton Street, Bell Green, etc. But there is no doubt that Brockely happens to have more brownfield sites suitable for development. There are a number of other houses that have been split into multiple occupancy over the last few years, but they don't touch the increase in housing provided on these brownfield sites.

There are many more brownfield sites around London, many vastly bigger than Bell Green, and many are beginning to be developed. North Greenwich is just one excellent example of this happening and I almost moved there 10 years ago.

Did anybody spot that the Talking Head reference? (Nothing but Towers)
[youtube]http://www.youtube.com/watch?v=c3t5nmgRVMs[/youtube]