Hi James
Most senior NCOs in the Militia were ex-Regulars who joined the Militia on the permanent staff after being discharged from the regular army. However, looking at his entry in the 1881 census all his children were born in Burnley, so he may have only served in the Militia.
Normal militiamen joined for six years, doing a 6-8 week ‘training’ each year. Any UK Militia could serve anywhere in the British Isles during the training, but most years they would just go to the nearest military training area. At certain times they could be used ‘in aid of the civil powers’ at time of unrest or during elections. Each year notices were posted in local newspapers calling out the Militia for the annual training, and the same source may tell you in which part of the UK they had served. My guess though is that he moved to Lancashire and enlisted in the Militia there, rather than the RL Militia going to Kerry. Or do you have information that he was in Ireland as a serving soldier?
Militia enlistment papers are in WO96 in Kew. If you cannot get to Kew Findmypast are putting them online. Before 1873 the Militia came under the Lord Lt of the county rather than the War Office. So a trip to the record offices in Burnley and Preston may yield something, or you could at least see if they have online catalogues.
This link gives some background to researching the Militia –
http://www.nationalarchives.gov.uk/catalogue/RdLeaflet.asp?sLeafletID=26Have you got the certificate for his second marriage in 1873, or birth certificates of the three oldest children? It would be useful to know how he is described before 1881.
Ken