Completely normal in the Philippines, also in Spain IIRC. If anything, what we do in the UK may cause problems over there. I had a huge problem trying to explain what my mothers name was in the government office when sorting our marriage licence. It was completely alien to them that my mother lost her maiden name upon marriage.
It's quite legal wherever. Frankly we can call ourselves whatever we want, and since the custom of making their last name their middle name after marriage will appear on any Filipino documents, there really wouldn't be a problem.
