U105 was issued number M 22-946, period listed as dates only between 02.01.1940 - 27.04.1940, she was however not lost until 02.06.1943. Also the same number was re-issued to U1020 on 10.02.1943 almost four months before U105 was sunk. Did U105 have an alternate mail number for the last few months before her loss? John