FourZeroCharlie
MIA

I’ve been thinking about the age. He looks very young and yet he’s a Corporal. That leads me to think he‘s probably 25 or thereabouts. Would that be a reasonable assumption for that time?
Oh, yes - very much so.
For every photo of a grizzled Pte, you'll trip over another of a fresh-faced Cpl or Sgt from that era.
We have a possible name, Sidney Tufnell, who would be the right age bracket but we’ve got no evidence of him joining the Army so far.
As you say, a cursory search has not turned up anything for that name.