Grandmother had a different name FBR application.

[daveandtrace]

Hello, Im hoping someone on here could please give me some advice with my Foreign Births Register application before i submit it.
I'm applying for Irish citizenship through FBR as my Grandmother was born in Tipperary but my mother was born in England.
I have managed to obtain all the necessary documentation and was about to submit it before we noticed a potential stumbling block.
We have my Grandmothers original copy of the Irish birth certificate with just her first name and the same surname of both her parents(Butler).
On her death certificate she also has the correct maiden name down as Butler.
Unfortunately on her English marriage certificate she has a different surname than what should have been her maiden name.
We believe she came across to England and fell pregnant with my mother or got pregnant in Ireland before she left for England and took on a different surname to make people believe she had got married in England and had not had a child out of wedlock.
We have carried out extensive online checks to see if there was evidence of another marriage but haven't found anything and none of the remaining family know anything about another marriage, apparently she chose the other name as she liked the name.
With the birth certificate there is clear proof of Irish nationality of my Grandmother also backed up by the maiden name on her death certificate.
The problem we have is there is no link to the assumed name on her marriage certificate and are worried this could cause an issue on the FBR application.
We think that this situation must have happened lots of times in the past and are hoping someone on here could share their experience of this and advise us on what to do or whether this will be a problem or not.
Many thanks for any help that can be given David.