In am researching RCAF-pilot Colin Frank Sorensen, who was shot down on 11 April 1943 in N Africa, cf.

81, 154 and 232 Sqdns was in combat with Ju 52 and 109s from JG 53. Ring and Shores describes the combat as follows:
"Meanwhile at 0900 Wg.Cdr.Berry led 12 Spilfires from 81 Squadron, 11 from 154 and 11 from 232 on a sweep over Tunis Bay at 23,000 feet. Over El Aouina Ju 52s were seen taking off and 232 Squadron dived to the attack; Bf 109s appeared overhead and ‘nibbled’ at the squadron during the dive and on the way home. Fl.Lt. Lynes set one Ju 52 partly on fire when PO Sorenson nipped in and finished it off, but was himself then jumped by a Bf 109 and shot down. Sgt. Kellar was seen to shoot down another transport in flames, but was then also shot down by a Bf 109, crashing into the sea. Lynes then attacked and shot down a further Ju 52 and FO Starnes also claimed one. During the return flight the Bf 109s kept up the attack, but PO Plummer got on the tail of one and gave it a four second burst whereupon it crashed. It seems likely that Sorenson and Kellar were shot down by Hpt. Tonne of I/JG 53, who claimed two Spitfires on this date."

Would anyone be able to guide me to further sources on the combat, and - especially - to details on the losses of Ju 52. From the above description it seems like the RAF force claims 4 Ju 52, but is this confirmed by German sources?