Just a couple of things, the last photo of the first post - that's an access road into Farnborough Airport which ran right the way through the middle of the site. And the last photo of the second post, behind that fence is Farnborough Airport itself, told you it was close!
An indoor straight rail setup for testing among other things harnesses, belts etc etc the rig would have accelerated down the track and come to a sudden stop at the end.
It's too late to see the place now unfortunatley it's almost all demolished now.