Indicative of an Irish entry, joined in Ireland. No regiment , and "odd" entry date, no rank, no age (no hope!)
Only one in WO338 is "Anthony" in RFA. His MIC had no address, but indicates that this man went on to an RAF commission, but I cannot find that.
1921 Mar 16. Joined ADRIC with service no 1839. Posted to C Coy
1921 Jul 2. Posted to D Coy
1922 Jan 20 . Discharged on demobilisation of ADRIC