I am wondering, If you somehow manage to come to an agrement ammicable with your ex in respect of maintenance can you just go to a sol and ask them to form a contract or does it have to go to the courts?
It will really depend how how much he will keep up his end of the agreement.
If you know without a doubt that he will pay you every week then you dont really need either of the above.
If you think he will miss payments here and there then court would set it in stone.
I'd have the payments set up as a DD from his account to yours thats proof enough that he has agreed to pay this amount. And if you did have to go to court at a later date he need to explain why he has just stopped paying.