It appears from different sources that a POW was given a number which was related to a Stalag, such as VI/357 the numbers I am seeing are in the 300s.
If a POW was moved to another camp, did he keep the original number or was he given a new number.
In two sources a web based one and the book Footprints On the Sands of Time, they show maybe one camp an airman was sent to, but I have found that some were actually moved to other camps but it is not noted in either of these sources.
POW's numbers were issued at their first camp they arrived at, usually not Dulag Luft though. Because of this, there are situations where two or more POW's have the same number. The German's cannot of been happy with this!
They kept their numbers from camp to camp unless, for some reason, there was a need to issue them with a new number. The VI/357 obviously refers to Stalag Luft 6 and stalag 357, Thorn/Fallingbostal.