Thanks hallmark and Sinann. My Michael Gilligan was baptised in 1829 in Kinnegad and the Michael Gilligan who passed in 1900 is the only one who comes close in correct age from civil records. My Greatgran was baptised at St Marys Kinnegad in 1854. We were fortunate that my Fathers Uncle lived into his 90's and was able to relate stories of his Mothers Father being the Head Gardener at Lowtown House when the Ray Family were living there. If he had died before 1864 (ie when she was 10 or less) then it would have more than likely have been mentioned. Problem is we have no knowledge of there being a youngest brother Michael. The baptisms stopped in 1859. The only missing one was Thomas in 1848 which I now believe to have occured in New York. Four came out to NZ, two went to Manchester, leaving only Mary from 1859 to track down.
OK. Sitting there rereading my post checking for typos when it hit me. So before anyone else suggests the obvious. "two went to Manchester" Yes there is a Michael Gilligan who died at Prescot in 1891 aged 63 circa birth 1828. Off to do a census look up request
Dang Different Michael. Almost needless to say he was from Ireland, but had a wife and a 27 year old son born in Prescot. So still looking for a Michael born over a widely fluctuating time span, possibly in Westmeath