ILR on Ancestry,problem with Grandparents change of Name

[larrymendel1]

Hi Guys.
I am applying on Ancestry grounds for ILR.I have been on an ancestral visa for the last 5 years,I tried to apply for ILR now on those grounds.
I am in serious trouble here. I have just received a letter of refusal of my ILR application.
As far as I am aware everything is in order except that my grandfather changed his name(don't ask me when or where)and I can't prove this thus the refusal.
I have written to them explaining my situation that I am unable to provide documentary evidence of name change.
The problem I have with this is that my ancestral visa was granted on these grounds. I only made an affidavit with the police in South Africa,swearing by oath that my grandfather is in actual fact the same person as stated on his birth certificate.My father got his British passport on these grounds and I got my visa. How am I supposed to prove this. Surely this has happened before.Loads of people have changed their names during the 20th century and there was no official record of this always.Somebody help!