Greetings!
I have done a similar project for you in the past and I can do it again. And finish it with haste, of course.
To show you I mean business I'll copy the part of your sample here:
PO Box 118,,Guildford,WA,6055
PO Box 174,,Walliston,WA,6925
GPO Box 9994,,Perth,WA,6848
Unit 6/57 Weir Road,Road,Malaga,WA,6090
PO Box 199,,Karrinyup,WA,6018
8 McKensie Grove,Grove,Kelmscott,WA,6111
PO Box 392,,Kelmscott,WA,6991
Unit 5, 16 Gutherie Street,Street,Osborne Park,WA,6017
Po Box 231,,Civic Square,ACT,2608
PO Box 264,,Kelmscott,WA,6991
1049 South Western Highway,,Cardup,WA,6122
,,,,
PO Box 332,,Claremont,WA,6910
P O Box 23,,Forrestfield,WA,6058
Unit 3, 24 Irvine Drive,Drive,Malaga,WA,6090
110 Bibra Drive,Drive,Bibra Lake,WA,6163
40 Haub Road,Road,Lake Clifton,WA,6215
108 Brown Street,Street,East Perth,WA,6004
As I can't attach a file, I've made a manipulation of your column with the first address and copied it here in a way that I've put a comma where one cell should end (the same in a csv file)
Kind regards,
Ratko I.