Just thought I would warn you about what happended to me in Rotterdam. I travel with my daughter perhap 6 times per year, and often get questioned as I am divorced from her father and therefore have a different name. They usually check a birth or marriage certifcate or ask daughter who she is travelling with. This time however they asked where the consent form was, I explained I knew nothing about a consent form and have never had one before. He said that since 2016 this is a legal requirement and you must have permission from the other parent. There is a form here www.mumsnet.com/pdf/recommended-consent-letter-for-children-travelling-abroad.pdf
I hope you all have reasonable exes who will fill in the form!