Thanks to everyone for your comments so far and all that you have said has been taken on board.
Michael, just to make it clear, the floor and timber panel hiding the ground row are in fact painted with matt green chromakey paint which is not quite the same shade as the green screen but slightly lighter.
On Friday we intend to re-rig the lighting set up, removing the ground row and reinstalling it on the top lighting bar. This lets us remove the timber panel totally and solve one problem. As to the floor, we are going to use 'blacks' (heavy black drapes) to minimise the bounce back from the space lights.
All of your suggestions will be tried and I'll let you know the outcome.
Thanks again, And I agree Phil, flying is a pain in the arse!!!