I have a copy of Oliver Charles will. He mentions his children: Charles Frances Purcell; Ernest Oliver Plunkett; Pelham Arthur Stanley Plunkett; Claude Ralph Allen Plunkett; Ethel Olive Plunkett; Mabel Evelyn Plunkett and Emma Norah Plunkett. However on his death certificate it mentions the presence of his son, Herbert Plunkett. Did he have 8 children? And why is he not mentioned in the will? Unless of course he uses another name.
Norah, you are a descendant of Emma (the youngest?)and it seems Kerry is a descendant of Emma's as well. And Jane, you are a descendant of Charles (the eldest?). Iwonder if any other 2nd cousins will turn up.
I don't know much more about Oliver's side of the family, but I'd be happy to find out birth dates if necessary as I presume they were all born in Dublin.
I did have a look at his address, Springfield in Leixlip. A lovely house that is now a hotel. Leixlip is a lovely village (small town) close to Dublin.