The "Debesco" mark appears to relate to "Debesco Works" an electroplating factory in Sheffield. In a period up to the mid 1950's this factory was the manufacturing center for "Lewis, Rose Company Ltd" a well-known manufacturer of electroplated and other flatware. From a “Sheffield Museum” reference it seems "Debesco" was in fact a trademark of "Lewis Rose" who started in 1922 and the mark had been used before their move to the thus known factory.
Yours
Fishless
Ps. sorry the image is a bit big.