Well I'm still waiting for Diggerman to come back with a quote for doing the main excavation of the entrance road (not something I can just tell him to get on with unfortunately, as it will possibly involve some shoring up). Until that's done I can't really start easily clearing the stuff out, and I really want to get on with that, and start treating the steelwork.
Also waiting for the historians to come back with anything! The possibility that the tunnel might be in any way noteworthy from a historical perspective has also contributed to my reticence in pushing forward!
Several times over the last few days, I've climbed down the ladder, squeezed through the slim gap in the rusty steel doors and paced the cool dark tunnel. Each time I still feel surprised that this thing has been hidden underneath the garden all that time! Whilst endless possibilities as to use spring to mind, just plain old easy access storage would be nice at the moment.
(I've also realised that you can only take so many photographs of a tunnel before they all become a little samey! - Another reason to crack on soon)