My flat has been bugged.
After we found the device hidden in the book case we hooked it up - it’s a very simple piece of kit, a USB jack, no encryption or anything - we downloaded some of the footage:
I now assume that whoever was here previously was downloading more footage from this camera.
I’ve posted the device’s details in a photo:-
I’m now in the process of getting the most expensive locks money can buy put onto every entry point in the flat.
UPDATE: Thought about calling the police in but not sure I want to have to explain everything that’s been going on. Is that dumb of me? Thoughts?