[Observer1940]

One has to consider that not all RAF aircraft lost over the sea in WW2 (even those given as Cat FB) were shot down.

My Grandfather's Whitley had been in touch by wireless per Raid Form (TNA, Kew). Also an SOS incident is recorded in Hants CRO, an SOS by unknown aircraft at BT Archives and an RAF Aircraft SOS per Air Ministry Distress file in AIR 2 at TNA, Kew, but there is no record of any wireless communication / SOS in the Squadron ORB at TNA, Kew, nor the Casualty file according to the claim by the AHB.

Mosquito
There is a file in The National Archives, Kew, in AVIA 5 for WW2 and although I have only listed the AIB Misc., Report Numbers (so that they don't get removed). These AIB Misc Reports have numerous Mosquito Serials, which were lost due to 'structural failure'.

Although yours may not be listed, you have to consider the possibilities of engine failure, structural failure or even the possibility of a fire on board.

Structural Spitfire Failures per AIB, but listed by RAF to Other Causes
I was interested in 3 Spitfire crashes which I discovered were all structural failure according to AIB reports at TNA, Kew and I wanted to know the AIB Engineering Branch which dealt with the Reports, so I wrote to the AHB who wrote back saying that according to their RAF records two were enemy action and the third was a Flying Accident.

Perhaps, the author was given the general term 'enemy action' when your Mosquito loss actually had another cause?

Mark