Likely your William Bradley-
Northern Whig, 19 May 1916: Mrs. Bradley, 20, Altcar Street, has been informed that her son, Private William J. Bradley, Royal Irish Fusiliers, is in the 2nd Western General Hospital, Old Trafford, suffering from gas poisoning. He is 21 ...
(also in Belfast Newsletter same date). From the above possibly born c1895 and father deceased by 1916.
Looks like Bradley family may have been at that address for quite a while.
Belfast Telegraph, 28 Jan.1944: PRISONERS OF THE GERMANS. Fusilier Joseph Campbell (Royal Irish Fusiliers), nephew of Mr. John Bradley, 20 Altcar Street, Belfast, previously reported missing, is a prisoner in German hands.
Belfast Telegraph, 10 Mar.1944: A radio letter from a Belfast war prisoner In Germany, 6949193 Fusilier ... has been received, addressed to Bradley, 20 Altcar Street.