Hogden Bottom (I think)

Try this image as a jigsaw

On the Brighton Road midway between Posts 163 and 164 marking the boundary between:
Reigate and Banstead / Croydon
Highways Authority / Transport for London - this being a trunk road

TQ 3120 6176. Someone sent me this picture and asked what is it? It is painted on a wall in Foxley Lane, Purley near the junction with Russell Hill Road, ie. at the junction with those two roads and the Purley Way and Pampisford Road.
The text is “DOT N^o. A23 1900 R”. DOT is Department of Transport, A23 is the road number and 1900 R is the entry in the DOT’s list. But list of what? The answer is: list of walls, bridges and other structures which were the responsibility of the DOT. (I think I have seen similar signs on bridges.) The name Department of Transport existed between 1976 and 1997. It and its successors are responsible for trunk roads except, as the "HA/TfL" notice in the previous image indicates Transport for London looks after this wall.

But why? At some stage, probably at the time of the creation of the Purley one-way system, this bit of Foxley Lane was widened necessitating a retaining wall which became the responsibility of the DOT.

Ditches Lane / Devilsden Wood. See its eventful life.

TQ 364 582 Limpsfield Road, Warlingham outside Sainsbury's.
The spots on this picture are, I believe, fog

TQ 36587 58364 Sunny Bank, Warlingham junction of Chelsham Road

Image has been flopped

not found

South side of Dartford Road/Old Bexley Lane on the present Bexley/Dartford boundary. Satellite images show the road surface changing about 5 yards to the right of the post’s present position. This is a good indication of the exact boundary. I think this post has been moved about 5 yards to the left so that it did not obstruct the Chinese take-away. Another strong indication is that its inscription plate is facing the hedge!

TQ 51197 73966 on the north corner of the junction of Melrose Avenue and Falstaff Close. The quarry mentioned by Martin Nail has been redeveloped as housing. No idea how far this post is from its original position. The people re-siting this post had a very strange idea: instead of sinking it into the ground, they stood it on the pavement and then encased its legs in concrete.