The post office were beyond useless, the travel agents didn't have a clue.
In the end, I emailed Passports.Athens@fco.gov.uk
and got this reply:
Dear Madam,
Please be assured that there will be no problem concerning your passport as long as is it is valid for duration of your trip to Greece.
Regards,
Maria
Nationality & Passport Section
British Embassy Athens
Tel: (0030) 210 727 2784
Fax: (0030) 210 727 2720
Thank Feta for that!
Thank you all so much for your replies.
Amanda
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