or Post 75
Posts 74 and 75 both probably lost forever during the building of the M25 which can be seen in the background of this image. The Wraysbury (or Wyrardisbury) River may well have been moved by a few yards.
Similarly Post 149 probably disappeared during the building of the M25. Compare with Posts 80 and 81 which appear to have been relocated during the building of the Wraysbury (or Wyrardisbury) Reservoir

Mad Bridge

The Nail list gives a description of TQ 037 770 on S bank of stream at NE corner of grounds of Poyle County Infants School.
It is probably the same school which is now called Pippins Primary School. A better grid ref for the post is probably TQ 0360 7692 and the post may be visible from Pippins Park accessed off Raymond Close

TQ 034 766 Poyle Pump S side of Bath Road about 10 yards E of junction with Dickens Place

Opposite side of bridge

with Plate 77 visible at far left

Reservoir sheep

Wraysbury Road, Staines

The London Stone - the great … great grandparent of the posts.

just upstream of Walton Bridge, near to Post 94

The Wikipedia article about Thames Conservancy shows this post