Not sure if this has been mentioned before but: at that part of the river where the steps are (and a little further along) how much red is in the water. Is it overgrown etc or just the river. Would you be able to place a body in throw the bank or would you need to be further in? I think some one has mentioned this in part before (can't remember who - sorry) but would you realistically murder someone and throw them in the river and just hope they are not seem at any point down the river for miles? (If the spot was closer to the Humber I can see this as a possibility). Apart from an initial though when she went missing, the water for me has never been part of it. Too much left to chance in that scenario at least from the park area.