Hi Dave, I just got married in Cagayan De Oro and I didnt have to get my cni stamped at London, I juat went to the consul in Cebu (moya Jackson) you can get her email on the British Embassy web site,if you want to go to her you will have to phone her up and make an appointment a couple of weeks before you go, Tel 0063 45 323 4187... her email has changed from when I emailed her but you should find it on the B/E site.
hope that bit of information helps you dave. cheers Ricky