I'd call the a Wizard CSA to them them you are going overseas, where you are going and that you intend to use the card, but nothing else.
Simply put it into credit and use it. You should be fine.
(As always, take a backup card with you.)
Had been planning to put it into credit , but by more than my limit. I was told that this was not recommended, indeed it could result in the card being blocked.
Next person I tried at CS told me that it WOULD be blocked if I went over it substantially.
She said money laundering issues, issues with cards being lost and inability to refund etc as a reason .
Anyway, it put a dent in my original plans. ONLY way around it seems to be if you continue to monitor online, payoff what you owe online and then reuse.
Negative is the loss of 'free' interest for the billing period. Positives are still the nil bank charges for ATM withdrawal and no added percentage charge for o/s transactions.