The complete code for this post is on GitHub.

maptools (which requires sp) is used to read the shapefiles.RColorBrewer provides the colour palatte.head(div@data)
# ID DIV_CODE DIVISION DIVI DIST_CODE DISTRICT DIST AREA_SQM
# 0 33 576 SPENCE SPEN 5 BELCONNEN BELC 1521080.3835514
# 1 34 562 WEETANGERA WEET 5 BELCONNEN BELC 1592959.57680176
# 2 28 558 MACQUARIE MACQ 5 BELCONNEN BELC 1725477.62080595
# 3 21 563 HAWKER HAWK 5 BELCONNEN BELC 1946411.66888773
# 4 17 560 FLOREY FLOR 5 BELCONNEN BELC 2758198.69610702
# 5 16 574 EVATT EVAT 5 BELCONNEN BELC 3033032.07047406
head(pcLoc)
# Pcode Locality State Comments
# 1 0200 AUSTRALIAN NATIONAL UNIVERSITY ACT
# 2 0221 BARTON ACT LVR
# 3 0800 DARWIN NT
# 4 0801 DARWIN NT GPO BOXES
# 5 0803 WAGAIT BEACH NT PO BOXES
# 6 0804 PARAP NT PO BOXES
# DeliveryOffice PreSortIndicator ParcelZone BSPnumber BSPname
# 1 AUSTRALIAN NATIONAL UNI LPO 150 N2 019 CANBERRA
# 2 CANBERRA SOUTH DC 150 N2 019 CANBERRA
# 3 DARWIN DELIVERY CENTRE 085 NT1 001 DARWIN
# 4 DARWIN GPO DELIVERY ANNEXE 085 NT1 001 DARWIN
# 5 WAGAIT STORE CPA 085 NT1 001 DARWIN
# 6 PARAP LPO 085 NT1 001 DARWIN
# Category
# 1 Post Office Boxes
# 2 LVR
# 3 Delivery Area
# 4 Post Office Boxes
# 5 Post Office Boxes
# 6 Post Office Boxes
The DIVISION variable in the shapefile is matched to the Locality variable in the Australia Post data to deduce the postcode of the DIVISION.
Need to figure out the best way to add a scale to the map.