I think Sydenham Society played a big part, maybe even instigated it. One of their local councillors is Chris Best, who seems very active, so that may well have helped. Unlike FH, Sydenham is (mostly) one council ward so it's easier to get coherent action. Unfortunately the centre of FH is split between Forest Hill and Perry Vale wards so it's difficult to get the various councillors to do some joined up thinking.