Last few days I have noticed the rear wiper sort of drifting in slow motion across the window all of its accord...... It seems to take 3or 4 little jumps to complete the full sweep.

Looks like a trip to Dealers.

Is this similar to the symptoms other members may have suffered with their rear wipers?

Another new motor required by the sound of it (or strip the old one and clean it up) My dealer replaced mine recently for £130