Last Night, 3 other mates and I decided to check out the middle head fortifications, so we checked out the place during the day (found a couple having a quickie near one of the tunnels, heard them all the way through) and then headed back at night to get into anywhere we could. We ended up getting into most of the upper level ones we wanted to get into (bar one because of our chubby friend who missed out) but we knew little about what else was below us, which leads me here for some others who have been down there and and have tips on where to find entrances