Pounds to Euros

You get the best economy by using your pounds in Britain and withdraw euros in Greece

I live in the UK.
Just thought you might get a better exchange rate in a Greek bank.
The exchange rate in the UK is very poor at the moment, £1 = 1.06 euros
My bank doesn't charge me for withdrawals from the ATM.

You will find it difficult beat the interbank rate, or even the interbank rate +1% if that is what the ATM / your bank offers (eg with a visa debit card rather than MasterCard).

The more specialist forex dealers in London can sometimes shave it down to .5% over the interbank rate if you are buying enough.

1.06 though isn't the interbank rate; at the time of writing it is 1.09428. The best UK bureau de change figure today is 1.09.