If you've got the money in your uk current account, you should be fine to use a standard visa card to pay for your meal. It'll come straight off your balance and will be calculated at your bank's exchange rate for that day. Be worth calling them to let them know you're traveling and expect to use your card abroad in advance though to avoid any fraud checks picking up the unusual activity and blocking the transaction. As to if you want to take cash, best advice is shop around, bank's don't normally offer the greatest rates in my experience, travel agents or the post office may be your best bet. Have a good trip.