Hi Stuart
Good luck on your trip to the Philippines. I too got engaged on leap year's day (but he asked me while he was here in the Philippines visiting). I remember how great the feeling was when he asked me to marry him. Do guys get the same feeling? Hehehe.
May I suggest that even though she had already asked you (which is quite odd for a Filipina imo), get to know her better whilst visiting her in the Philippines, and if you truly feel that she's the one for you, why not ask HER to marry you, and make it official that way. It would mean the world to her, coz many Filipinas love romance, and trust me, she will never ever forget it.
Keep us posted!
Lee