I just called Santander. They said they cannot pre-authorise a transaction. But assure me it will go through. And if there is any issues with it. I would be contacted soon after. When i have been in the Philippines. I have always contacted the Fraud Department to let them know i am in the country. They wanted to know how long i would be staying. They told me that my Debt Card would be fine until that date. However i am doing this transaction from the UK. Let's see.