help please! regarding the law on children

I'm currently in the process of a custody battle with my ex. I have residency and their father has contact, we live 100 miles away from each other and for the past 3 years I've always taken the children to his doorstep but now after all the stress he has caused me (accusing me of abuse and sexual abuse to my own children because he wants custody!) I am no longer willing to take the kids to see him, I am however allow him to collect the children from my door and return them to my door. my question is the court isn't happy about this and wants me agree to meet him half way... do I HAVE to do this? I am responsible for this? the way I see it is if he wants to see them he can come see them... thank you in advance. ::::::::;;;; EDIT:::::::::::: I forgot to add that there is no court order as of yet stating I have to meet him half way, we are waiting for the next hearing to determine contact and to reconsider residency after the social services have completed a section 7 report because of the allegation he has made (which has proven to be false by police and child services and they closed the case) he is the one breaking contact orders by not bringing them back at the agreed date. I just wanted to know if I was legally required to do half of the transportation without a court order saying so.