In 1914, Martin Brady was living in Coleford, where he worked as a cook. He signed on with RGA on 21 November 1914 in Bristol.
He deserted from Plymouth on 28 January 1915 and was listed as a deserter in the Police Gazette on 16 February 1915. A court of enquiry was held on 26 February 1915 to discuss his case and to make a list of his belongings.
There is no reference to a Martin Brady being born in Gloucestershire or in online records that follow his desertion. He has a surname that is common in Ireland, so it is possible he escaped to Ireland.