Catherine Sullivan c1810 Help please.

Hello lovely people, I really hope someone can solve this for me. For years I have been looking for Catherine, her father Jeremiah, (c1780)  brother Patrick (c1811) sister Honora (c1816) and brother Jeremiah (c1821) in Ireland. They all went to London probably early 1820's and certaily all there by the 1841 Census. They lived in and around Spitalsfield, probably working in the markets as the professions are given as fruiterer and greengrocer. I have never seen any definite records of her mother.

Catherine married a John or James Kelly, in London, and had 5 boys, her husband was likely deceased by 1841 as she states she is a widow. I did a DNA test and uploaded the results to Gedmatch and I have a Gedmatch number, which I've used to try and pinpoint an area of possible origin, I do have a lot of slight matches around the Castletownbere area, given it was over 5 generations ago, I wouldn't expect to get any close matches.

I would dearly love to know where they were from, so that I can go and have a look around for myself, I am in Cork and I wouldn't be surprised if I've driven past their homeland numerous times!

I also have a question about a Tuomy/Toomey ancestor but I'll do that in another post. Thank you in advance.