I imagine under normal circumstances you can't just set out contact arrangements and expect that to be what you get (I mean for anyone, not just you, but with your ex especially so!). I do think it gives a starting point to which he can either object and suggest something else - which, if he were a normal bloke, would be what he did, but as he isn't..... no he won't agree, and the chances are he'll say nothing, write nothing, do nothing as he usually does, and that plays into your hands vis a vis the reasonable aspect: showing himself to be completely unreasonable even in this serious matter. There will be a paper trail. Oh, need to tag on a date by which, if he's not indicated otherwise, it will be taken as agreement. Make it soon (due to imminence of school start date nothing to do with getting it over and done with oh no).
So then, the Court will see that the mediators have refused to deal with him,
that he has dragged his feet unreasonably over the sorting out of the house
that he has been unfair with regard to spending time with ds over the holidays,
is unreasonable about letting you know when they'll be back after his unreasonable trip away with ds,
has been unreasonable about taking ds out after school and the time he gets him home by,
has been unreasonable about pick ups and drop offs
and all the rest of.
There's quite a lot there, possibly even enough to ask for contact to take place under supervision. So, if you haven't been making notes already, start now. Try to remember as much as you can and get as good dates as you can - w/c 9 June 2013.....
I know you're exhausted, FV, and I know that saying 'nearly there' is no comfort to you at all, but you will get there because there really is only one direction to go now.