upnorth, I believe those were actually Ju-88s.
From http://en.wikipedia.org/wiki/Short_Sunderland :
"Although the .303 guns lacked range and hitting power the Sunderland had a fair number of them and it was a well-built machine that was hard to destroy. On 3 April 1940, a Sunderland operating off Norway was attacked by six German Junkers Ju 88 light bombers and managed to shoot one down, damage another enough to send it off to a forced landing and drove off the rest. The Germans were supposed to have nicknamed the Sunderland the "Fliegende Stachelschweine" (Flying Porcupine) due to its defensive firepower and to the several prominent antennas protuding from it."
Edit: Oops, seems I was a bit premature there :)
"
The rifle-calibre .303 guns were far from satisfactory as they lacked hitting power but the Sunderland retained its reputation for being able to take care of itself. This reputation was enhanced by a savage air battle between eight Ju 88C long-range heavy fighters and a single RAAF Sunderland Mark III on June 2, 1943. There were 11 crewmen on board the Sunderland, including nine Australians and two British. The crew was on an anti-submarine patrol and also searching for remains of BOAC Flight 777, an airliner that had left Gibraltar the day before and subsequently been shot down over the Bay of Biscay.
In the late afternoon one of the crew spotted the eight Ju 88s. Bombs and depth charges were dumped while the pilot, Walker, redlined the engines. Two Ju 88s made passes at the flying boat, one from each side, scoring hits while the Sunderland went through wild "corkscrew" evasive manoeuvres. The fighters managed to knock out one engine. On the third pass of the fighters, the top-turret gunner managed to shoot one down. Another Ju 88 disabled the tail turret but the next fighter that made a pass was bracketed by the top and nose turrets and shot down as well.
Still another fighter attacked, smashing the Sunderland's radio gear, wounding most of the crew in varying degrees and mortally wounding one of the side gunners. A Ju 88 tried to attack from the rear but the tail turret gunner had managed to regain some control over the turret and shot it down. The surviving fighters pressed home their attacks despite the losses. The nose gunner chewed up one of the fighters and set one of its engines on fire. Two more of the attackers were thoroughly shot up and the other two finally decided they had had enough and departed. Luftwaffe records indicate these were the only two that made it back to base.
The Sunderland was a wreck. The crew threw everything they could overboard and nursed the aircraft back to the Cornish coast where Walker managed to land and beach it. The crew waded ashore, carrying their dead comrade, while the surf broke the Sunderland up. Walker received the Distinguished Service Order and several of the other crew received medals as well. Walker went on to a ground job while the rest of the crew was given a new Sunderland. That Sunderland and its crew disappeared without a trace over the Bay of Biscay two months later after reporting by radio that they were under attack by six Ju 88s."