The scenery suggests the tunnel near Box which isn't Box Tunnel, but I have no idea what it's called.
It is indeed the tunnel at Box between the site of Mill Lane and Box stations, which I think I saw referred to as "Middle Hill Tunnel" or something like that
(Confirmed by Dogbox's post made while I wrote this). It was taken from the same bridge that you can take a picture of the famous box tunnel from. The view the other way:
