Plans shows that this was called New Mole Battery and Alexandra Casemates. THe plans are dated 1882 but this relates to the later Alexandra Battery which was built over the older Casemated Battery which faced westwards.
The Casemated battery was build in 1866 with four 9-ins RML guns. When the South Mole was built three of the casemates were destroyed to allow for an access road to be built. The remaining casemate and underground works were recently used by the Fire Services for training and have therefore sustained smoke damage.