OK I'll try with the information I have so far. I'm also not 100% if the information on their wedding certificate is 100% true. It seems she may have been 4-5 months pregnant when they got married, not sure if family approval was given, so it would make sense there may be some discrepancies but unfortunately makes things harder! I have doubts if she even gave her proper name.
So the grandmother
: Mary Aspin nee Hart , died - 01.01.1931 aged 46
Grandfather ; George Aspin no information
They had 5-6 children, most of whom I've seen their birth certs for online so I'm OK with them.
I think she was from waterford, and he was originally from Kilkenny. I always thought he had a second wife after Mary, but if what I've found online so far is correct then he married Mary as a widower, first wife was Anne Martin from.kilkenny. (Marriage and death certs online)
So it works out Mary would have been born around 1888. The only birth certs around that time I can find is two sisters Mary Ellen Hart 1886 and Elizabeth Hart 1888. (Their father is William Hart, but according to Mary's marriage cert her father is William...)
Although both George's Marriage certs also have different names for his father.
The variants of their surnames Hart/Harte
Aspin/Aspen/Aspil/Aspel
I'll try looking for Georges birth cert now via Kilkenny as I'm not sure if I just looked through Waterford before.