Robert came up with this German claim: 'On this day Olt.Heinz Schopper from stII(J)/Tr186 claimed one Sunderland as shot down off Norway.'
Olt. Schopper flew a Bf109E.
I consider it very likely that he was the one that damaged Sunderland N9028.
As far as I know no Sunderlands were lost this day, not by 204 Sqdn nor by the other Sunderlands squadrons.