BCP 272 Tilley. We knew this one would be deep by the hint but didn't expect it to be quite so deep. I used the metal detector to confirm that there was actually something way down there before attempting to excavate the bottom of the existing hole that was already close to a meter deep. I was laying face down (hey, I was 'planking' ... cool) with head and shoulders down into the hole digging away excess dirt when I made contact with cap. For a cap that is so well covered, it sure has taken a beating over the years, probably as part of work on the canal. TFTCap.