Just got this in a sale at my nearest Homebase. The following region hack has been tried and confirmed to be working on the PET706/05...
Open the disc tray
Press SETUP
Go to "Preferences" & Press OK
Press 212225
Press ARROW LEFT, ARROW DOWN
Current RC should be displayed
Press the button for the desired RC (0=codefree)
Press SETUP
Close the disc tray
Hope that helps!