DD's father has turned up suddenly (after an almost 8yr absence)

Not wanting to deny DD a relationship with him DD spent the weekend with him 3weeks ago (1night and a day) he then called CS and said circumstances have now changed and he has DD 50% of the time (which according to CS was one weekend a fortnight) So he then had her again this past weekend. I didn't want to challenge this as he is eligable for legal aid and I am not. So not having DD for years and wanting to butter her up I guess he has been buying her small things and taking her bowling, movies, the local show, fishing etc DD currently thinks he is wonderful. Now he has told DD he wants her this weekend to take her somewhere else which I planned to taking her to. And DD wants to go with him as currently he is so much more fun then me. I told DD I am taking her as its my weekend and he can decide when it suits and when it doesn't and DD seems happy with that.

The problem is he is turning up late to pick her up and just arriving at my house which I dont approve of. In the past he would walk in and check everything out so I want to meet him at an arranged place at an arranged time. I tried to do this but he was 1.5hours late with me sitting on the side of the road waiting with a screaming 3yr old. So now I want to go to mediation to arrange very specific times in which we met and drop of DD thats very clinical or professional as he deliberately goes out of his way to inconvenience me and my family. Does any one know how I go about this to ensure times are stuck to and he can't get away with been late or not turning up? Like Easter he was having her and called 2weeks later to say he wanted her.