Quote Originally Posted by jazbernsina View Post
Hi, we live in the UK and my wife is Filipina, now a British citizen. On the application form for her British passport, she needs to give the date of marriage of her parents, who separated many years ago, and neither of them can remember the date they got married.

We need help to get this information, and was wondering if you had any ideas how please.

Salamat!
As I recall, my wife also faced such questions. Even at the passport interview they insisted to ask about her grandparents key dates.

If she didn't know she just put 'not known'

After all the key info of both parents were given at the time of application for naturalisation (DOB, Place OB, Full name and Maiden Names).
Besides, not all parents actually get married.

As Graham suggests, if you are really concerned just give the Passport people a phone call.