This boat sunk in Operation Deadlight on December 17th, in Axel Niestle's updated book German U-boat Losses, he lists her as having foundered at the site she was due to be sunk, while previous claims on her demise that she was sunk by Naval gunfire [Ships names not listed]. This area had been designated the site for aircraft deployed to sink U-boats, but on this day air operations had been cancelled. If she had been sunk by the navy, then HMS Onslow and HMS Cubitt should be the ships responsible as they had already accounted for the U779 on the same day and position.
As for U483 and U1301, also both sunk in Deadlight, but on the 16th, again the cause of their sinking is not accurately stated, both listed as being victims of the RAF, but, unlike other air victims no Squadron is listed. One cause of their loss I have been suggested to try, that both were attacked and damaged by aircraft but, it was left to the ships that towed them out to finally sink them.The web sites for the known squadrons have not helped, but before I try the navigating through National Archives, I wonder if anyone as any details of any of these three U-boats. john