Ok i recently got married in the Philippines so perhaps my experience might answer some of your questions:-
1) Obtained CNI from registrar here in the UK after waiting 21 days....i didnt get it authorised by a solicitor.
2) flew to manilla with the CNI and my then partners CENOMAR , live birth certificate, my birth certificate, previous wifes death certificate and previous marriage certificate...and the fee. Got up early to visit British Embassy at 7:45 (i think it was) when it opened.
3). They exchanged the CNI for one acceptable to the Philippines authorities on payment of the fee....same day service....infact done within one hour but i was first in the que.
4). flew to Tacloban and next day went to Basey SAmar registrar office to apply for the Marriage Certificate. As we were both over 21 no seminar needed. lots of photocopying was done!
5) After 10 days (working days ) minimum we collect the Certificate from the registrar.
6). Found two witnesses and a judge who agreed to marry us after looking very closely at all the papers.
( i think my wife managed to pull a few strings here as she seems to be related to half the population of Basey).
7) gotmarried on 27th August...i arived there in Manilla the evening of the 12th and was at the embassy on the 13th. registrars on the 14th!. so not counting weekends it was tight doing it in 21 days!
Hope this helps you a bit!
