Hello my name is ***** ***** I will help you.
Did your neighbour give a reason for doing this please?
Ok. Well it is a shared boundary which means if they are going to do anything you and them need to agree. They can't just hack the ivy down.
This would be criminal damage, therefore you can inform the police and your neighbour could be arrested, charged and taken before the court.
It's disgraceful that the neighbour has cut this down without your permission. Therefore you can complain to the police because clearly he is guilty of criminal damage.
Also you can sue for loss and damage caused. You could issue proceedings in the county court for the distress and inconvenience caused.
So no, they can't change things to the shared boundary it without consultation.
Can I clairfy anything for you about this today please?
Of course just ask for me. If this answers your question could I invite you to rate my answer before you go today, otherwise the site doesn’t pay me for the time spent with you. Thanks in advance and good luck.