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That said - 80%"not found" is a pretty high percentage.
I just take it that someone, somewhere in the world at some recent time has been seeing those rankings.
There's already quite a bit of discussion over there about "Top Search Queries" - probably worth having a look around.
There is no way the .org.uk would have been seen at such a high position as it is a very new site, whereas the Australian site (same name, no other connection whatsoever) is many years old.
Do you have people in other locations who could check their local results or search via a proxy to see if it's just your local results that don't tally?
Although you can't guarantee that you will actually see results from any one DC you could try a multi-DC search to see what results you get.
[edited by: tedster at 9:26 am (utc) on June 9, 2008]