How about I just walk into the post office masturbating? Will I get a free passport instantly ?
You'll get some free travel and probably some free board and lodging at “Her Majesty’s Pleasure”.

How about I just walk into the post office masturbating? Will I get a free passport instantly ?
Because the country you visit wants to know your passport will still be valid during your stay.
6 months left. Regardless of location as far as I'm aware.
Get that updated now, passport renewal doesn't take more than a week these days. Hugely efficient.
Send forms off this afternoon from the post office, have it next Friday. I am willing to put money on it.
This.Pay another £8.75 at the post office and they will check your form and send it off for you.
2 weeks to the day for mine, that was last month.Just under two weeks when mine was done in January.
6 months left. Regardless of location as far as I'm aware.
I've heard the 6 month figure before, but logically what's the point of an expiry date if you can't use it up until the expiry?
Seeing as Greece is in the EU I don't think there'll be any problems.
OP, make sure you apply for the E111 card too! It's health insurance for EU countries. Apply online, no cost, and mine (for example) arrived in a week.