I understand the comment about overlooking, however, the patio that the deck is on, is at that level, and the lower section of the garden is only 2 foot below that. I currently have a very clear view of their garden and straight through their kitchen window simply by standing on my lawn. So whilst I acknowledge I have enlarged the area with the higher vantage point, there is virtually no difference to the level of privacy. The hill is so steep that we are on, that is the way it is. My neighbour up the hill, if I stand on the deck, I am looking at his waist!
Anyway, that aside, all useful info.
I am happy to split the deck and lower a section, not so useful for our purposes, but we do want to try and keep everyone happy. So need to wait to see what LA say to that suggestion. I just don't want them to now insist on planning unless I remove. I guess the answer is, I have removed the offending deck and replaced with one that is no longer more than 300mm above ground level at any point. I don't have money for planning and then also to have to make changes should the initial planning be refused. This whole episode has just soured what was a positive change to our house meaning that the kids could finally use the back garden.