In reply to Emilio Bachini:
Cheers all who have e mailed me and posted. The archway is on the footpath that runs between Shuttleworth lane (near Cosby golf club) and Cottage lane which comes out of Broughton Astley. The best parking is at the Cosby end of the footpath.
The following pic should give an idea of scale, the crack is slap bang in the middle of the tunnel so should be dry all year round.
https://www.ukclimbing.com/user/profile.php?id=334#&gid=1&pid=6
I have merged a couple of shots taken from either side of the tunnel to show the crack going the full span of the arch.
https://www.ukclimbing.com/user/profile.php?id=334#&gid=1&pid=5
https://www.ukclimbing.com/user/profile.php?id=334#&gid=1&pid=4
Would be nice to know what people think if they do get on it
Post edited at 11:22