[richardtheforth]

 I understand from friends who still live in the area that it has gone massively upmarket with Penge high street more like Shoreditch with artisan delis, hipster cafés and some very nice places to eat. I find all that difficult to imagine.

Ha Ha, not quite! We lived between Anerley and Birkbeck stations in the late 90s: CP, Anerley, Penge and Sydenham were still very, er, vibrant back then.  CP and Anerley have changed most since then, biggest lurch upmarket was when the East London Line extension came to CP and Anerley. Sydenham has benefitted from this too, but also benefits from being close to 'South Londons posh' Dulwich, so people can move to Sydenham and tell others they live in 'Dulwich borders'. 
Penge is still Penge.

As much as I love those atmospheric youtube vids of the racing I'm glad there's no longer motor racing in the park, it's such a lovely tranquil oasis of calm and family fun, and there's plenty of other places for racing, Brands Hatch is pretty close! 
Anyway, look forward to seeing more the track!