i may be stepping on my toes here, but i will breifly give you what i know. my great nan (my mums nan) was a denigan at birth. she never really spoke much of her family, indeed she claimed not to be irish. although further reseach show her father whomever he was was irish. my mother has the father of her nan as richard denigan, born abt 1882 in longford ireland, she has a copy of the marriage in which he gives his name as richard denigan. he also names his father as james. she alo has him on the 1901 census as richard.
i would not take this as his name literally though, if your james and our richard are the same person and the father was james it might be that he used his middle name. of course it could be a coincidence that you have a james denigan marrying a amy revell, and we have almost similar but i dont think it is. we have yet to find any birth record for a richard denigan, and although the irish records are scetchy, the denigans were RC and would have baptised their children, meaning there should be a record somewhere.
im sure my mum will get back to you soon, so please keep checking back xxxxx