I used the Night Riviera for the first time on 8th June 2022 and really enjoyed the experience. I slept better than expected and the coaches - although older - were quieter and less rattly than the Caledonian. We had a loco attached to the rear, which apparently was detached at Reading.
I travelled with my bike, and it was relatively easy to book it for a space in Coach A.
I made a film about the trip which is on YouTube:-  https://youtu.be/AyVAbBlmvXU