Perhaps the cousin should review the family information. I find no Thomas Burns marriage in 1903 in the Newcastle district.
Recap - the only Royal Scots Fusilier of that name who appears on the CWGC site is the one who died at Loos in 1915
Wife Martha
Came from Troqueer Kirkcudbrightshire
Lived Maxwell Town Dumfrieshire
May be worth checking the regiment also, there are other regiments with very similar names.
MaxD