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My second British Passport has expired and the application for renewal was rejected on the basis that the following documentation required in Section 2 of the application form was necessary:

• 1) Unabridged Birth Certificate for my Father.
  2) Unabridged Birth Certificate for myself.
  3) Unabridged Marriage Certificate for my parents.

I was born in Harare (then Salisbury) in 1962, and both passports were issued by the British High Commission Consular Section Pretoria in 1980 and 1990. The 1990 passport was submitted with the application and it clearly indicates I am a British Citizen.

I have obtained a "Certified Copy of an Entry of Birth given at the General Register Office" for my father who was born in the UK in 1935. However, obtaining items 2 and 3 are somewhat problematic. Both my parents are deceased and there is no documentation in my possession for the marriage. My birth certificate is also "missing".
There is a person in Zimbabwe who has offered to obtain these on my behalf at a rather hefty cost. Obviously this is somewhat risky as the payment is required up front in US$, and I may end up out of pocket and emptyhanded.

Does anyone have advice in this regard? Is it possible, that record of my birth could be obtained from the General Register Office?

Hope someone here can advise me.