Here it is
🔗115412[linkphoto]115412[/linkphoto][/link]
Called an Offset or Setoff it was usually a means of connecting a pump plunger to the main rod in a way that kept the rod clear of the pump. However we are here looking up above drainage adit so it was possibly connected to a balance bob.
The shaft is full of interesting bits and pieces. The steel clamps are correctly called "staples". At the bottom are the strapping plates of an angle bob, probably the surface bob.
There are 3 upper levels above adit, maybe with a balance bob still there. We may find out some day.
My avatar is a poor likeness.