G'Day Cate,
For consistency, set up both Windows AND Outlook
for the correct Region/Time Zone:
Windows:
a) Start>Control Panel>Date and Time
Time Zone (Tab)
Select the correct Time Zone
Check "Automatically........daylight........."
b) Start>Control Panel>Regional and Language Options
Regional Options (Tab)
In the "Standards and formats" section, verify
the correct Language/Region - this also
sets the FORMATS for Windows (and
Outlook) generally
Outlook:
Tools>Options>Preferences (Tab)
Calendar Preferences (Button)
Time Zone (Button)
Select the correct Time Zone
Check the Box "Adjust....daylight savings..."
The principal determinant of Date format is Windows (b).