DCS has 3 entries for OSM;
Imagery - that is what you are using for building footprints, hte base map does not show them. 
Topographical .. good for large things - like the big power lines as it shows the voltages .
Base Map - shows the addresses.

Note: Six Maps is commercial .. and they will protect their copyright. Use the DCS Base Map .. it should be an option in your editor .. In Josm .. under 'Imagery' select 'Map' then select 'DCS Base Map' Please try to avoid using other sources .. unless they are on the https://wiki.openstreetmap.org/wiki/Australian_Data_Sources 