Weekend Visits

When my partner & his wife seperated they went to court to work out the financial arrangements & child visitation arrangements etc.(4 years ago - divorced last year), at that time he received paperwork from the court (which is now missing) that he had could access to his children every 2nd weekend. Over the course over the last 4 years - she constantly will refuse him the right to see his children, or dictates when he can/can't take them on holidays (which is usually can't unless it is a weekend/overnight Saturday)

His ex wife constantly refuses to allow his children to stay with him (throughout this year he has had them on a total of 3 weekends over 5 months), she makes excuses every 2nd weekend, from the kids are sick;  accusing him of not looking after the children properly or speaking negative to the kids & benig a bad influence; to the kids don't want to sleep at his house and don't want to see him (but when he speaks to the 3 kids - they say they would like to & that they miss him.

Anyways, as yuo can guess - there is always different excuses - first she says he can have them, then at the last minute she can't be contacted or changes her mind, so he doesn't get to see them.

He has spoken to child support with no luck, to a magistrate with no luck...could you please advise what he can do & approximate costings of what he can do to have a legal plan drawn up of when he can & can't have them - something that she will be required by law to adhere to? I thought the origianl court order was something she had to adhere to, but even the police have told him they can't do anything about it.

Any input is greatly appreciated!

Thank you!