This is very interesting A. I have a database of about 600 Shudalls so it's always interesting trying to fit in another bit of information.
What you have just said ties into what another researcher, Brian Coughlin, said. He also had Mary of 1885 and George of 1888 being born ot Thomas Shudall and Mary Murray. And the census records and civil registration records link this to the Thomas who was born in 1864, which ties to the marriage record of a Thomas Shudall in 1884.
So I would suggest your next step would be to go to the GRO site and order a (photocopy) cert for either his birth (preferable) or his marriage. The second will give his father's name (which you know) and his place of residence at the time of marriage. The first will give his place of birth and the names of both of his parents. Once these details are known I can see if he might fit into the lines I already know of.
But of course I see one puzzling thing in what you have said here - how did your g.grandmother come to be a g.grandmother if she didn't have any children? Perhaps she had children before she married this Thomas?
Where do you live? I ask as these Shudalls were originally from London.
E.