This structure is located just above the road that leads to the Great Siege Tunnels, Willis’s Road. It would appear that this is a WW2 structure, but the observation side may have been earlier.
The structure appears to have two sides, one for observation and the other held some type of instrument or weapon.
The observation side, on the west, is very similar in construction to the observation post at Rooke Battery, built over the old Battery Command Post. Neither position seems to have had a roof, allowing occupants a good view of the skye on all sides.
The instrument side of the structure, which may also have held an anti aircraft weapon, has the tie downs for some gun or instrument with six medium size bolts.
Exact use of this position not know if anyone can help.