Retired engineer here,,,,,, build up the sides of the lower panel by about 3 inches, clad in tin foil and Bob's your uncle.
![Cool 8)](http://www.threetownsforum.co.uk/forum/Smileys/default/cool.gif)
Fit to ceiling with pulley system.
It's quite simple really, oh by the way, don't speak of violence to birds, ME reads this sometimes.
SORRY ME.
![Shocked :o](http://www.threetownsforum.co.uk/forum/Smileys/default/shocked.gif)