Thank you for your question
My name is ***** ***** I shall do my best to help you
1. It is common courtesy for you to be given notice when people are going to come to the house. Sadly you cannot exclude his new partner - but you can make it plain that your ex must attend as well
2. You do not have to deal with his partner at all. There are no laws that forbid it - but you can simply refuse to deal with the new partner on this or any other matter
3. You are correct having the lead does not mean he can exclude you.
You need to write a clear calm letter setting out the new terms and making it clear that you will only go forward on these terms
Please ask if you need further dteails
May I ask how old the children are?
I should have made it clear - "property" includes the garden!
You can write a second letter saying that for the avoidance of doubt if they continue to turn up without notice you will report it to the police as
You can indeed do so since you will have given fair warning.
You are still obeying the Order - and your ex will find himself in difficult if he suggest anything else