Hi Daniele,
To add a little more to the story, a report from a German reconnaissance aircraft at 12:50 on 15 July 1942 placed the 'cruiser' in 03 Ost/7864, course 90 degrees, speed 27 knots. That location is off Bone, Algeria.
From British Y-Service reports: "On 15/7, aircraft of K.Gr. 806 were heard during an attack on the cruiser 'Welshman'; one sustained a damaged engine and was obliged to have escort back to base."
K.G. 77 seems to have been transferring to Crete and then North Africa on 15 and 16 July 1942, and as Rudi says, I./K.G. 54 was resting (according to it's war diary).
So that might be mystery solved, unless anyone has additional information.
Cheers,
Andrew A.
Air War Publications -
www.airwarpublications.com