William Campbell born 1912 or 1913 - secret marriage!

   I am trying to locate where a William Campbell (born between 03/12/1912 - 02/12/1913) was originally from in Ireland. His father was called Thomas Campbell (and was deceased by 1944). All I do know that William was a soldier during the 2nd World War and was living at Albany Barracks on the Isle of Wight in 1944. At 31, I doubt he was a private, so may have been higher up the ranks, but no idea of his regiment. He was 31 when he married my grandmother on the 12th July 1944 in Sittingbourne in Kent, England. She was English and called Irene Edith Smith and was 19 when she married him. This was a secret marriage to all of us up until her death,  and she never divorced him. Does anybody know of anyone with that name, who would have been in these barracks in 1944. Long shot I know!! The marriage certificate doesn't give a date of birth or born address, so stabbing in the dark here. All I remember is her saying that she returned to Ireland with him, & returned back to England a few days later!  Any information with regards to regiment or birth county may set me on some road to discovery. Many thanks for reading this far!