Oblt Kayser, 1./406 and an incident on 26.7.40

[Adam]

I'm looking for details on an Oblt Kayser who was StaKa of 1./406 in 1940.
He was involved in a combat on 26.7.40 with a Sunderland aircraft in K6+CH in which the flight engineer was wounded. (The aircraft suffered only four hits from the Sunderland before the engagement was broken off).

I'd like to know Kayser's first name and tenure as StaKa
The name of the wounded airman

and (even though in the wrong forum)
The identity and squadron to which the Sunderland belonged.

Thanks in advance