Travelodge, Cardiff Bay, the last time I visited.
You can enter the back passage/entrance and get in a lift without walking past the Reception Desk, but you might be on CCTV, you go up in the lift to the chosen floor AND THEN you are confronted by a carded door to get onto that landing. However the guest can come from their room and open the landing door.
You may meet another desk and the landing/door may be monitored by CCTV.