'Just Jane' Lancaster bomber--Why does she have the 'City of Sheffield' crest on her?

Question

Also, what is the bulb shape for on her underbelly near the rear??

Answer 1

Sheffield was bombed so the crest could be for that.

Answer 2

The name 'Just Jane' was applied to the port side, inspired by a popular 1940s newspaper comic strip character. The title ‘City of Sheffield’ is carried on the starboard side in honour of the City’s steel works that provided many parts for the Lancaster, its Merlin engines and the weapons it would carry.

Answer 3

not sure about the crest but the bulge at the rear of the fusealage will be the blister for the H2S which was a downward looking radar designed to help with navigation  that was fitted to a lot of late war bombers, it painted a picture which helped navigators identify where the aircraft was, unfortunatley the germans developed a reciever which allowed night fighters to home in on the signal and find the bombers