UK Ancestry Visa when grandfather's surname is inconsistent

[caid]

Hiya, Visa experts!

I recently applied for a UK Ancestry visa - my maternal grandfather was born in Wales. Still waiting on the outcome, but I'm fairly worried because his surname on his birth certificate is spelled differently from his surname on his marriage certificate/my mother's birth cert etc.

On his birth cert (b1926), it's spelled "Dicken", whereas on his marriage certificate and my mother's birth certificate, it's spelled Dickin.
My entire family use "Dickin", and had no idea it was ever any different. Why the discrepancy? I have no clue, and he's since passed away, so I'll probably never know. It certainly was never legally changed.

Is my application likely to be declined because of it? If they do decline it, how do I get round it?

Thanks in advance for any advice