I just like to thank everyone who has replied with advice or commented so far. I'm pretty sure I'm going to remove the staircase. It's large and my wife doesn't like it anyway. If I can find a way of using screening as a safety and privacy barrier without planning permission then I'm far more likely to be allowed the decking, green would probably be more to the council's liking. Hopefully I'll get hold of Bexley's Duty Planning Officer today and I'll update on here. Many thanks for everyone's kind guidance.