Strange series of events, but here goes.
A couple of days ago, I noticed a faint hum/whine at low speeds on over-run and, I think, when turning right, that appeared to be coming from the front nearside. But after a few miles, it went away. But same again this morning.
Then, at lunchtime, there was a similar but louder noise when I engaged reverse (even when not moving) and it continued until I changed gear. Tonight, when I left work there was no noise, but it was back again when I got home and engaged reverse.
All other gears are fine and changing is smooth.
Any ideas folks?