The name of POW 31334seems to be James Lesley Rixon Grey,an Australian Why does this not tally with other data?

The information that I have indicates,or seems to indicate ,that POW 31334was held at STALAG 344 from June 1941-April 1945.He could not,if this is correct,have a service history in the active armed forces after this. Any comments or solutions please.