Can I make sure she can’t claim for maintenance in the future?

March 22, 2015

I have been paying maintenance on my 2yr old through CSA as a private agreement with my ex wife broke down some time ago.
For reasons between us we have decided to step out of each others’ lives for good – her moving down south and me moving overseas.
She has contacted CSA and requested they cancel her claim so payments will no longer be taken through them.
So my question is, I am aware that she can decide to make a new claim in the future – but can’t claim for any back payments from the time in between the two claims. But though we have agreed NOW to sever contact completely and there not be any maintenance, she can be quite changeable and I’m concerned she may start it up again in the future on a whim.
Is there anyway to draw up or arrange some sort of legal document that states she won’t be able to make a claim for maintenance in the future?