jimawilliams, thanks.
I am not familiar with the area, and would not have guessed it without your "Upnor Castle" clue.
And, since the cricket field no longer exists, modern maps and Google Earth would not have helped.
I incorrectly started looking for footbridges over railways.
Anyway, I was here a couple of years ago. That is my bike, not a lightweight railway maintenance vehicle. Where was I?