Whilst I cannot prove it 100%, one of my 9th Bn men, J Blake, probably deserted during or after the Boer War. He enlisted with a pal J Ryan and his pal was killed in 1901.
In 1914 J Ryan enlisted and was sent to gallipoli and wounded there. A local newspaper mentioned this in October 1915. Blake probably did not think that the local paper would mention men wounded.
Then we come to 14 December 1916 - both men listed as with 1st Bn -
12419 J Blake died of wounds and is buried in Dromesnil Comm Cem (only 2 graves) whilst 12419 J Ryan died of wounds and is on the Thiepval memorial.
I am fairly certain that J Blake used his old pals name in 1914 and after being wounded, either confessed or was found out. He was then sent to France with 2nd Bn.
It would seem that the authorities were just happy to have him back! It is obvious that the paperwork failed to mention that Blake and Ryan were one man and therefore he is buried as one and commemorated as the other.
The death certs are identical and the MIC are identical. They have the same number and to my knowledge never served together
I think the forces were happy to turn a blind eye in most cases and men returned to the fold to fight.