Rooftop Gardens Revamped

The insides of the water tank have been problematic from the start. What colour should they be? What is the best use for the sunken parts to the east side which were a planning requirement to deter us from overlooking the neighbouring gardens?

On the matter of colour we have tried dark green, which looked er, dark. Then rust red which looked er, rusty. Daughter Lorna has better taste than at least one of her parents so she was consulted about colour - room by room and the inside of the tank. Her recommendations were accepted in full, in accordance with family tradition and bitter experience. The actual colour changes are being adopted from the top down, starting with the insides of the tank - which are now light grey - and by Jove it works. I hope you agree: