Benchmark

I was intrigued 3 weeks ago by a benchmark blipped by Rock_Dr and looked up on the OS Benchmark Archive map where my nearest benchmarks are.  Apparently I pass three on my daily walk.  Unfortunately I have completely failed to find them.  However, a couple of days ago, I spotted this one a couple of hundred yards in the opposite direction.  I only noticed it because the light was raking across it.  This brick pillar, at the entrance to the local farm, used to be the base of a taller brick pillar with a post box in it.  One day a couple of years ago a large vehicle swinging into the farm entrance demolished the top.  The Post Office picked up their mangled letter box and the farmer put the loose bricks in a gateway, and this stump remains - with its benchmark!  On the map it says "L B SE SIDE RD 9.1M N ENT MANOR FM 229.758M".