I birthed and stayed at St.Georges. That was in 2010, though, and the building has changed (after the earthquake). Rooms were nice and back then definitely all single rooms, assume that the same applies. Good food, good staff. Lots of help available if needed (was baby number 2 for me though so I think 1st time mums probably get the priority) and they were happy to show me how to bath baby etc if required. Very positive experience . Only downside is that you aren't allowed to take baby outside of the room unless in the bassinett. This probably applies at most places though.
HTH