 Complete the following phrase:  50 Squadron continued operations by night, taking part in the RAFs strategic bombing offensive against the Germans through the remainder of 1940 and 1941. It re-equipped with Avro Manchesters from April 1942. The Manchester was disappointing, however, with unreliable engines and had a lower ceiling than the Hampden it replaced. Despite these problems, 50 Squadron continued in operations, contributing 17 Manchesters to 