British postwar submarine propulsion experiments

Were the British interested in testing German submarine engines?

Yes, but German systems were only one part of extensive British propulsion research in the late 1940s and early 1950s.

Britain tested captured German ideas while pursuing several independent concepts of its own. Submarine-propulsion research was a major defense-spending item in the late 1940s and early 1950s. Liquefied-natural-gas proposals were among the alternatives examined. Captured technology therefore sat within a broader national research program rather than serving as the sole origin of British development.