Rickman- could you not come to an agreement between the two of you. my xp also refuses to pay the amount of money set by the csa, so I put forward a figure and he agreed . Only you can cancell the csa claim, but you need to tell them to keep your file open so that if he starts been a twat about that too you can go back to them at anypoint.
Don't know if this will be of any help, but Ihope it will.
My DD is now 8 and starting to coplaing about her dad herself now. she does know a little of what has happened in the past between me and her dad. When she brings up things I aleways try to turn it around saying -wasn't that present nice of daddy, or get her to talk about a fun day out she has had with him. (few and far between though)