In the Single Euro Payments Area (SEPA), which covers most of Europe, your card fees will continue to be free.
You can find a full list of countries in the SEPA at metrobankonline.co.uk/card-abroad.
Outside of the SEPA, our fees have changed:
From 10 January 2019
Non-Sterling Transaction Fee 2.99%
Cash Withdrawal 2.99%
Cash Withdrawal £1.50
So if I interpret this correctly, the fee on a Thai ATM withdrawal would be 2.99% + £1.50 + 150 baht.
So 15000 baht whould cost you £350.20 with a hypothetical zero loss transaction.
It's actually going to cost you £366.14, so that's a loss of 4.55%
Now, we never get to a zero loss transaction, but I know two ways that get close to 0.5% loss (cash in the airport rail terminal & Transferwise).
So I'm not keen to throw away another 4%. This is simply price gouging.
Incidentally, when I opened an account at Metro bank, several years ago, the reason was to take advantage of the 0% charge on overseas cash withdrawals.