How wonderful to read that you were able to uncover your Irish roots. :) I would love to see if I can point you in the right direction for more information.
Where did you find the lead to County Mayo and Meath? Was it by any chance mentioned on their immigration records or papers? During Griffith's Valuation
(1847 - 1864) there were a total of 28 households by the name Bagnell
on the island of Ireland. Four of these households were living in County Meath, and none in County Mayo
The same goes for the name Bagnal
, which is a name that is quite rare. During Griffith's Valuation there were only two households by that name on the whole island, and one of these was located in County Meath as well.
In this case I recommend reaching out to the genealogy centre in County Meath
, as they look after all of the remaining church and parish records from before 1864, when civil registration was introduced in Ireland.
I hope some of the experts here will be able to look into your question as well, and please don't hesitate to reach out if there is anything else you need.