Hi there :-)

I read the message slightly differently (I believe some of the supposed 'w's are 'u's and one of your 'F' s is I believe a 'G'. As follows:

AOAKN HVPKD FNFJW YIDDC RQXSR DJHFP GOVFN MIAPX PABUZ WYYNP CMPNW HJRZH NLXKG MEMKK ONOIB AKEEQ UAOTA RBQRH DJOFM TPZEH LKXGH RGGHT JRZCQ FNKTQ KLDTS GQIRW AOAKN

Also do you know who 'Mason' is? Maybe the person who sent in the photo? Is this a recruiting sergeant for GCHQ? :-))

Not being a code breaker myself what relevance does AOAKN have? Beginning and end of message.

This pigeon was found in a chimney - what can we learn from that? What was the procedure when a message was sent but not received? This can be solved :-)