I am not sure if Mary Ann would be the brother to William Allen (my 3 times great gradnfather), William Allen was a saddler living in Burt (my 3 times great grandfather).
I meant I cant make out James Allen father William Allen's job on the wedding certifcate that was the one i meant
This James doesnt appear on the census but the wife Ellen does
in the 1901/11 James Allen doesnt appear http://www.census.nationalarchives.ie/pages/1901/Donegal/Burt/Mulleny/1189529/ Same for the 1911 census