Gunner J Chadwick was a member of the Royal Artillery, Service No. 870709, POW No. 4535. Source: UK, British Prisoners of War, 1939-1945 accessed through Ancestry.com.
John (Len) was wounded in the same bomb raid that killed Michael Cister.
Kevin Byrne refers to this man as Leonard on the back of the photograph however there is no L Chadwick recorded as a POW at Wolfsberg. Further, there were three 18A Chadwick's to choose from. I chose this man as his POW No was the closest to the majority of Klagenfurt POW numbers. It's very possible though that the identification I have given this 'Leonard' Chadwick is not correct.