https://www.gov.uk/looking-after-children-divorce/apply-for-court-order
How to make arrangements for your children if you divorce or separate, mediation and how to apply for a court order if you cannot agree.
child arrangementsmakingdivorceseparateapply
https://www.gov.uk/government/publications/enforcing-a-child-arrangements-order-cb5
Find out when and how you can apply to the court to enforce a child arrangements order.
child arrangements ordergov ukenforcing
https://www.gov.uk/government/publications/form-c78-application-for-attachment-of-a-warning-notice-to-a-child-arrangements-order
Use this form if you have a child arrangements order (originally a contact order) that was made before 8 December 2008 and you want to apply for a warning...
warning noticeapplicationattachmentchild