Paul these are the northern M objects.
M81 and M82 (declination +69) are visible from Darwin but not from Perth.
Perth is latitude -32 so you can see to Declination +58 in theory but +48 or +53 is more like it.
I have seen M97 from my place at latitude -29.
Messier Type Declination
M 51 GALXY +47 12
M 106 GALXY +47 18
M 39 OPNCL +48 26
M 76 PLNNB +51 35
M 109 GALXY +53 22
M 101 GALXY +54 21
M 97 PLNNB +55 01
M 108 GALXY +55 40
M 103 OPNCL +60 39
M 52 OPNCL +61 35
M 81 GALXY +69 04
M 82 GALXY +69 41
Here are images of all the M objects.
http://picasaweb.google.com/dunlop1826/Messier#