To start with a hell of a lot of aircraft were lost on that night, as you probably know. Assuming that he identified the aircraft correctly as a Lancaster, then of the following the possibles are marked in bold. It should be noted that his claim was over the North Sea:
JA692 Lost in the target are (hamburg)
ED468 crashed on takeoff
ED616 Shotdown by Flak in the target locale
ED782 Shot down by a night-fighter and crashed into the North Sea. All but two of the crew were found and buried ED862 Lost without trace
EE172 Shotdown by night fighter (not a candidate because it seems to have been shotdown over land)
ED822 Shotdown by night fighter (not a candidate because it seems to have been shotdown over land)
ED535 shot down by a night-fighter (Lippe-Weissenfeld of 111./NJG1)
JA689 shot down by a night-fighter (Lövenich of II./ JG 300)
ED534 Lost without trace
ED931 Shot down by a night-fighter, exploded and crashed at Tostedt.
ED598 shot down by a night-fighter (not a candidate because it seems to have been shotdown over land)
However, it may not have been a Lancaster!
It maybe worth asking in the Luftwaffe section of
Luftwaffe and Allied Air Forces Discussion Forum - Powered by vBulletin as there are many experts who have access to original documents etc