Believe it not there are 3 Liberty James'.
2 were in the R.F.A. Both drivers & with pretty much consecutive numbers, 135259 & 135261.So joined at the same time. 135261 died 26/7/1919 (3rd. Div. Ammo Column). Son of Mrs. B. James. (according to the census m. Brittania).
The 3rd. is 18772 Pte. 7/Dorsets transferred to the 4th. Res. Batt. (202672) & never went overseas.
Occ. Hawker.
Attested 1916 aged 19. (b. 1897).
Add. Rossmore Village Upper Parkstone. Father Sansom James. (according to the census m. Kate).
Discharged 1918 as being medically unfit.
So according to this the one that served in the Dorsets isn't your man or the one that died in 1919.
Sanson(m) James 31729 D.C.L.I. & 644803 L.C. (364 Coy.). Also says ex RDC but not sure that's correct.
Attested 28/3/16.
Discharged 23/9/18 (wounds).