I was on Malta last week (3-10 January) and took the photos of Hagar Qim and Mnajdra on Monday 5th January. I was, luckily for me, allowed into Hagar Qim but work seemed to have progressed further at Mnajdra and it was closed. They said they were waiting for a "window of windless opportunity" in order to get the roofs up.
On Thursday 8th I was able to view the monstrous steel structures from across the landscape, so the covers had not been raised by then.
A shadow will soon fall over these temples, not to be raised for many years.
Thanks for the update. Let's see what the next four weeks bring them! I'm not so fussed if an even shadow falls across them if it protects them - whether it's the right shadow is a different matter. If the canopies are clear then you'll get those structures creating nasty shadows across bits, which will look naff on photos. An opaque canopy will, at least, give an even ambient light.