These Platform Mirrors can be found at station ends where the driver can see the full length of the train. They are used to aid the Operator in the door closing procedure where they can close the doors safely so injury is not caused to passengers.
These platform markers aid the driver into the correct stopping position for the Train. This particular style is used with the newer S Stock found on the Circle, District Hammersmith & City and Metropolitan Lines.
Typical London Underground bench found at station platform, I’ve noticed this wooden style is almost always found on surface platforms and not on any of the sub-surface/deep tube platforms.