U-Boat victories and claims

[Adriano Baumgartner]

John and Nick,
That what I was looking for...I know for instance that 248 Squadron was sent once to patrol an area where U-Boats were reported to be active - a kind ofa a "rendez-vous" ( perhaps an Intelligence report that must have come from ULTRA intercepts ). The result was that U-976 was attacked by Tsé-Tsé aircrafts and damaged on the spot the U-Boats and ships were supposed to be!
JOHN, from what you said we can assume that RAF Y Service could have listened to those communications - between Kriegsmarine HQs and U-Boats? I read somewhere and can "confirm" that messages from Almirant Canaris, who asked about his dogs were intercepted! So, we can "assume" that from time to time, this kind of "position message" that was not answered could inform the RN as well the RAF that a U-Boat was lost?!
BUT again, it is not very clear to me, HOW the U-Boat victories were confirmed to aircrew who were in combat against them. I mean, for a air-to-air victory one must have a witness, or a wreck, or bodies to confirm the victory, wasn´t that? However, were the U-Boat claims only confirmed by the mission report submited by the aircrew, after a long and tiresome flight and fight?!
Yours ( thanks again for the help...it is a subject that I´ve not read much about, so the vast amount of questions and doubts about how the system worked at that time...Please, do not be offended, if I often return to the same questions and aspects of this technical and personal doubt )
Adriano