Interesting! - but they ae different circuits, albeit a couple of miles apart. The fifties 'bike circuit is actually in the centre of the current theme park about here - http://maps.google.co.uk/maps?f=q&hl...,0.009613&z=17
Roughly triangular with the start (?) straight running along the top of the map, then turning right around the lake with the swan-boats in, down to Towers Hairpin at the bottom of the picture, then back up (along the trees) to the start/finish straight.
I'll try and scan the plan from the programme later.