After listening to Vicky's advice from the tutorial, and focusing on how the water didn't have to be blue, Laura came up the idea of making it black instead as if the dancers are deep underwater. This would mean that we could use a black screen / curtain instead of a green one and hopefully lessen the amount of complicated effects etc we would have to use. She showed us this image as reference :

I then went away and found other underwater photography that use darkness in their pieces to get more of a feel to how it looks and how ours may turn out. This is kind of like a mood board of darker images.