I think that letter is the block you're in, the first number is the floor you're on in that block and the other two numbers are the room number on that floor......not entirely sure though so please correct me if I'm wrong!!
lady montford is fine! its all in seperate blocks and i THINK its about 12ish ppl to a floor, or in ur little area neway. all of the ones i went in were rennovated and were much newer than mcnair,rankin, sailsbury etc, so dont worry! seriousl though the state of the halls really doesnt matter! once u settle in and start makin friends it wont bother you at all! but yeh, lady montford was nice so dont worry!
morton is basically the same as lady montford and its on the carnatic site so its about 15/20min bus ride into uni then you want into town which is about 5 mins straight down either brownlow hill or mount pleasant