German submarines arriving in England according to the Weekly Intelligence Summary No. 15 for the week ending 29 March 1919

An item reported the arrival of three German submarines at Harwich, England. The submarine found derelict and which arrived on tow at Gorleston, England on 22 March seemed to be the SMS U.C. 109 leaving Germany on the 15th.

Source

The National Archives, Kew Gardens, England CAB-24-77-68