Your link doesn't work (probably the stupidly long URLs generated by the photo library) but if it's file 20111220ran811596_029.jpg then yes, it's a Mexeflote. One element of optical confusion may come from the bow section being unlocked from the rest of the raft and lashed to the beach at an angle. Apart from that, the raft is hard up against the port side of the dock, there's probably a couple of feet clearance on the other side: look at the shadow. I can't remember for sure, but I think there is just enough room to walk/clamber beside a Mexe in the dock. The dock was designed to accept Mexeflote and LCU Mk10, so it's sized to be big enough for those, but no bigger.
I note from the caption that they plan a ship's company of 158, more than double the basic RFA ship's company, and about the number I'd have guessed the RN would have manned a Bay with. The basic RFA complement is of course only sufficient for basic operations and does not include Mexe drivers (about 5 per raft) or stevedores (about 10 in a detachment). I'll guess the RAN will have more medics (5?), a permanent flight deck/aviation team (10 more bodies?), an amphibious operations department. I can't think who else you might add until WEs become necessary with Phalanx and other sophisticated weapon installations. I'd love to see a breakdown of the RAN crew by departments.