Great pics. Often walk along northwestern part of the peri track (top of of Frans 744's first pic). Think most of the dispersals evident are now grassed over? The blast pens are still there, but the only concrete I can recall are top left of the airfield and top right corner adjacent to the 21 threshold where the VGS usually camp out when launching to the south.
My walk takes me across the valley and round the chalk pit when I can stop and watch the gliding for a bit longer.
Presume the "public footpath" (use it at your peril!), now a tatty strip of concrete or tarmac, is where the public road ran before the site became the airfield Douglas Bader would recall.
They now have some crowd control barriers set up in the vicinity of the runway thresholds in an attempt to stop wayward civilians wandering onto the live site while gliding is taking place. If it works the requirement to fence of the central grass won't be necessary.