What is a prohibited steps order and would this help me? (im in uk)?

I have only just been awarded weekly access/visitation of my 18 month old son as my ex refused me access after i met someone new in september 2010. now this has been awarded, my ex is saying she wont turn up to the meeting point the judge has ordered and says she is gonna move to the other side of the country to stop the access. (childish i know) its been suggested to me that i ask for a PROHIBITED STEPS ORDER next time im in court. what is this, what does it mean and would it help me i really do want to be involved in my little boys life?