Hello
While your ex doesn't need your agreement to move 50 miles away with the children, she can't change the children's schools without your involvement and agreement; or permission from the court.
Your only legal option is to make an application for a Prohibited Steps Order under s7 of the Children Act 1988. This wouldn't prevent mum from moving, but it would prevent her from moving your children out of their current location. You would need to prove that moving them away would be detrimental to them, ie:
• The other parent is acting unilaterally, disrupting the children’s well-established routine, and shared parenting with you is being terminated without regard to the children’s best interests;
• The other parent’s relocation will effectively erase you from your children’s life or significantly reduce the amount of time your children can spend with you;
• You suspect the other parent’s motives, as there was no discussion with you to seek viable alternatives;
• The other parent has no pressing need to relocate, so you believe it has been done to prevent contact;
• Removal from the area is not in your children’s best interests as they are settled at school and moving them away would interrupt their relationships with teachers, friends, other relatives, and, of course, yourself
However, I don't wish to get your hopes up as judges don't like to restrict personal movement of a parent, and your ex may believe that she has a good case in moving your children, ie to move to be closer to her new partner for support. The problem with applying for a PSO to restrict internal relocation is that it can be viewed as controlling and with school aged children it is often better to apply for a PSO on the grounds that a change of school and loosing friendships would be disruptive. A PSO application won't necessarily stop the move but court proceedings ensure that proper arrangements are in place before the move takes place.
Your best option is to come to an agreement with your ex - if you present it as a fight, then it will become hostile. You need to present the arguments against her relocation from a child-focused perspective. Booking some
mediation sessions is a good step. It might be an idea to ask her to set out how she thinks contact will work if she does move. How often, who will travel, who will pay for the travel, how will your children cope with the travel, etc. Your arguments should not be about her moving, but about removing your children from their schools, family, friends, disrupting their routine etc. Stay child-focused.
Both you and your ex have parental responsibility, this means (in theory) that you are both equal in the eyes of the law - one parent does not have an elevated status re the children over the other parent. There are certain decisions that both parents MUST be involved in and agree upon (or where there is no agreement, permission from the court):
• Selecting a school and applying for admissions;
• Contact rotas during school holidays;
• Planned medical and dental treatment;
• Stopping medication prescribed by a GP;
• Attendance at school functions (so the parents may avoid meeting each other wherever possible);
• Age at which children are allowed to watch age-restricted DVDs and video games.
It may be worth thinking about applying for a Child Arrangements Order, with a "joint lives with" element ( shared residence) with clearly defined times and days/weeks when the children will live with you, and live with thier Mum.
Another option would be to offer to move to her new area in order to continue with the current arrangements.....
Or for your children to live with you, and Mum has contact on the basis you current have.....