The involved aircraft was a Liberator (86 Sqn RAF/V) and I have some doubts about the story that the Soviet submarine dived when the aircraft approached, even if they were in a position where they weren't supposed to be.
As I am more interested in the U-boats I haven't checked the details of this case yet, but these two documents held by the National Archives should contain all known information about this incident:
Royal Navy Enquiry: ADM 1/16390 (
http://discovery.nationalarchives.go...ils/r/C4786876)
Royal Air Force Enquiry: AIR 2/9279 (
http://discovery.nationalarchives.go...ils/r/C2634443)