Model year 2003 UK 2005 US Roof unserviceable, diagnosis outer left piston snapped in two! Hi, Replacement piston has arrived the problem is WIS says open the roof to proceed with the swap out. With the piston gone the roof no longer operates so you assume you can open the roof manually. On the previous model you used a special key as per the description in the owners manual on this model there is now easily identifiable procedure to open the roof manually certainly nothing in the owners manual. Has anyone ever opened this particular model manually? Cheers, Howard.