Juli 25.1940 and III/StG 1?????

[cbe2009]

Hello!
The matter concerns Ogr. Josef Stillinger, a gunner from 8./StG 1 and decorated with EK I and II.
On the above mentioned date he fell in battle with english fighters.
This is mentioned in both "The battle of Britain - then and now" and in "STUKA" by Helmut Mahlke.
Mahlke says, that all aircraft returned, but Stillinger drowned and was never recovered from the sea. The death card in my possession says the same.
My questions are:
1 Could it be, that Josef Stillinger fell or jumped out of the aircraft?
2 Who was the pilot in this plane?
3 Is it possible to give the aircraft a code and Wnr?

I know, these are tough questions, but everything helps
Thanks in advance
Christian