Interestingly, if I go 'Cmd-K' in the Finder and look in the 'Recent Servers' drop down (the clock icon) I can see an afp://169.blah.blah.blah item in there. It's not an address I've added, so something's put it there automatically.

Try clearing the Recent Servers list, also have a look in your Keychain to see if there's an entry there, and remove it if so.
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simon