I am looking for information on my Grandad's brother who was part of Squadron 461 and went missing, presumed dead, and am a little confused about where to go next. Any help would be greatly appreciated.

I have accessed all records from the National Archives, and have so far pieced together this much.

The first time the crew of Sunderland Aircraft (EK 578) "E" of No. 461 Squadron RAAF was shot down was in 1943, in the Bay of Biscay on 16/09/1943, but were rescued. At this time, Sgt. P.R Criddle was Third Wireless Operator.

The second time was on 1/10/1944, ML735 "A" and the archives casualty list states F/Sgt P R Criddle was part of the crew.

My Grandad lost all information on his elder brother and I am trying to find as much as I can, but don't really know how.

Thank you