I have a 2014 Greenline estate and my load cover has started to mis-behave. When I close the tailgate with the load cover fully retracted it somehow hits he load cover and it shoots back to half-way. It's not done this before and now it does it every time! It's rather irritating. Does anyone have any experience of this or any ideas?

Check that the load cover is holding correctly in place on both sides of the boot. I had issues with the hooks on one side of my boot leading to the cover retracting at random on hitting bumps. You'll see a diagonal wrinkle in the load cover if it's not held evenly at both sides. Some powered boots have a function that automatically releases the cover as you described, but it's only supposed to happen when you open the boot - it's a setting in the maxidot menu on cars that have it.