Thank you for your question
My name is ***** ***** I shall do my best to help you
It is not Contempt of Court - but it does mean that your ex has breached the Court Order and you can go back for an enforcement Order - with the threat of Community Service or a fine for your ex.
I would suggest that you write a polite letter to your ex pointing out that her mother's actions were a breach of the Order and could lead to your ex receiving Community Service of you have to apply to enforce the order
You should also write a polite letter to the Centre Coordinator asking her to ensure that her staff are aware of what a Court Order looks like
Please ask if you need further details