As you stand looking towards the castle from the bridge over the moat, the old Killer Whale enclosure comprised the right-hand portion of the current sealion enclosure.
I should also have mentioned "as Brum described on the other photo" - sorry Brum. The book "Dolphins - Kings of the sea" has some good photographs of Cuddles being moved into the pool (I think John Dineley may have them on his site too) with David Taylor and Don Robinson in attendance.