Freelander sunroofs are notoriously fragile and prone to failure - but you've found that out. I've had mine replaced twice under warranty.
Is the mechanism making ratchity sounds? If so a gear is probably stripped. You can try to physically help it close by pushing it forward while pressing the close button. Or if it is in the last phase where only the aft end is open, it might help to gently press down on it while pressing the close button. Both of these are just to get the damn thing closed so it doesn't rain in and the mechanism is truely shot and needs replacing.
You could try opening it slightly and then try closing it, making sure the air deflector is retracting properly (one on my failure modes). If that is the problem, you can carefully remove the air deflector and the roof itself works almost normally. Just chuck it in the back and return it to the dealer at the next service.
If nothing happens when you press the close button, check the fuse. That is the easiest but probably the least likely fix.
Good luck. I hope you are still under warranty since the replacement is pretty expensive. Needless to say, I don't use mine very much any more and definitely not off-road where it might get too much vibration and fly apart!