Another stab in the dark:
Michael Bannon is listed in the 1911 census as 70 years old. He was born in 1841 or so. He has a son named Michael. Griffith's Valuation was done in the 1840s.
Griffith's Valuation is available (free) athttp://www.askaboutireland.ie/griffith-valuation/
If you do a Name Search for Michael Bannon in Co. Westmeath in the Union of Ballymahon, you get only 1 result, in the townland of Cartroncoragh, parish of Drumraney. So this might be a relative (or might not).