You're probably not aware of this site: it covers the local history for most of Lewisham, including Sydenham and Forest Hill, using photographs, maps and illustrations. It's really great... You can even access the scans in decent quality if you know what to do. Check it:
http://picasaweb.google.com/lewishamheritage
It's a bit like Ideal Home's Suburbia in Focus. If you know anymore sites like this then please don't hesitate to post and share the links!