David - Here as you suggested is my postcodezones file:

# A list of TiVo postcodes and the timezones that they represent
# Two columns, separated by one tab only.
#
00800 Pacific/Auckland
02000 Australia/Sydney
02600 Australia/Sydney
03000 Australia/Melbourne
04000 Australia/Brisbane
05000 Australia/Adelaide
06000 Australia/Perth
07000 Australia/Hobart

Note though that this has been the same for the five years I've been happily running the TiVo. Note also that I've tried to GS using 00800 and that had no affect on the outcome.

David