Hi Felicity
I agree with Frances and Jean , I think Gertrude might have been born out of the UK. I searched for any Gertrude born 1865 - 1875 in Lancashire on UK FreeBMD and no one looked anything like Brancker. Also on Brian Lawsons site , Census Index 1871 of the Isle Of Man, there is nobody by the name of Brancker, or anything close, which makes it unlikely she was born there.
The same applies to Charles Henry , so he may be related. Can't find his death in England either. Cancel that , on a second run found him born 27/5/1858 , with Father John.
Searched IGI for her birth anywhere , did not get a result , but found in the Bahamas the births of Clara Viola Branker 1883 and James Charles Branker 1884 to parents Charles and Gertrude ........another posting ?
Could not find a death for Gertrude's father Charles in the UK 1871-1892.
There is another Gertrude Brancker , aged 32 on 1891 census in London , born Lytham Lancashire. I also cannot find her birth on UK FreeBMD.
As far as Gertrude's marriage document on the IGI , I am not sure if it is Brancker or Braucker, too hard to tell
Cheers
David Dwyer