Obviously I need my birth certificate when I go to get married in Philippines next June/July....

But can anyone clarify that the one with my adopted surname is ok (I was known by a different surname for my first 4 years of life!) I am in the possession of two birth certificates. One is a small one that has no mention of me being adopted but the date of issue was 4 years after my birth (when I was adopted) And the second (A4 size) says certified to be a true copy of of an entry in the adopted children register. This was issued in 2003 when I had an interview that needed a CRB check doing and at that point I didn't have a birth certificate and only found out then that I was adopted!!! My Mum never told me as she is my birth mother and the man who adopted me was her second husband. I have and have never had anything to do with my birth father and have always known my Mums second husband as Dad.
Anyway my Mum found the smaller birth certificate a few years ago and gave it to me, but like I say they both have my adopted surname, is this likely to cause trouble anywhere along the line? I am not sure if I can get an original birth certificate with my original surname on it. But should I try?