We've seen this or one like it here before. British occupation zone of post-war Germany; at first issued to the police in Oldenburg, then in Lüneburg, both cities in Lower Saxony not too far from each other.

All other markings are consistent with a late-1944 shipped Lend-lease British Service Revolver.

What's interesting is that this gun was not surplussed out by the Germans, but apparently was handed back to the British and then taken out of service in Britain, as attested by the pre-1955 post-war commercial British proofs.