We went in Spring 2016.
I'll skip over all the main tunnel before the sand and side shafts which go down.
Beyond the collapse
We walked up and beyond the sand and then up the collapsed rocks.
Then climbed up over the collapsed rocks and looked back at the thick brickwork of the arch. See photo.
After walking further forward along the huge rocks we found a way in to the boulder choke on the left.
A tight climb through the boulders for about 5 minutes and it opened up into a living room sized cavity.
Inside that space lower down on the right is just the top of the arch of the other side of the tunnel.
The gap under the arch top is big enough for someone to get through but very damp and muddy.
We didn't have any rope to descend into it so we threw a glow stick into it which just disappeared.
Would have liked to have gone further but went back out through the boulder choke.
We'd probably do the bolder choke again.
Steep shaft out
We couldn't resist investigating the wind blowing out of the hole in concrete blocks on the east side of the main tunnel.
We climbed through the hole and started up the shaft.
Pretty much all the corrugated ceiling has fallen onto the floor and skates around on the rocks as your walk on it.
There are a few huge wooden support beams which are balanced on their ends.
Knocked one of them sideways by accident which was terrifying for 3 seconds.
Much of the way up the floor was so loose rocks were tumbling onto the people behind.
The ceiling is visible and loose most of the way up and gets increasingly sandy.
After what felt like 300 meters of scrambling we got to the end and could see plenty of daylight.
The last 5 meters are sandy, tight and have almost nothing to grab onto to climb up.
5 minutes of contentious pushing up off the crumbling sides and a shove from below got one of us out.
That exhilarated person than pulled the rest of us out once we'd scrambled far enough to the light. See photo.
After we got out we saw we were on a hill with bike tracks at thew bottom. See photo.
Looking south we could see trees but couldn't see the road close to the main tunnel entrance.
We would definitely not climb that shaft again.