Found this concrete structure right next to the gate to the base of the service reservoir. The roof is gone. I remember I read some article mentioning the defenders blew up the battery structures before they retreat.
Some other articles had mentioned the Aberdeen Battery had been an improvised one with two 4 inch guns. Earlier before I went up the hill trying to look for traces of the remains of these, but I don't know what I've found has anything to do with them:
