I had a similar sensation/sound when I first purchased mine (RWD conversion) and after changing diff/trans fluid and cleaning the filter/screen, the noise completely disappeared.
Yep, could be a possibility... as i said in earlier posts, as long as it doesn't damage the car, I'm OK with it... CheersSorry just saw this and responding to the opening post.
That sort of behaviour and noise sounds quite like a tightly locking LSD. I have had various race cars and they all do that at low speeds when tightly turning and can be almost impossible to reverse in. It is possible that the clutch plates in the LSD have somehow welded together which might happen in an old car with very low mileage like yours that has obviously been parked-up for long periods.
Just a thought.