Hello, this is Jim, a dual-qualified lawyer (UK & Republic of Ireland) and happy to help you today.
The thing to bear in mind is not to use physical force. And do not take a weapon, a dog, or anything to make them think they might be in physical danger. The reason being they can contact the Police (for assault - which includes the reasonable apprehension of physical harm).
You can tell them you will apply for an injunction from the local county court - which if breaches means they face a prison term for contempt of court. Your injunction application would succeed due to trespass on their part.
If they become abusive then feel free to contact the Police - the usual number is ***** but if you need them in an emergency then it's the 999 number.
If nothing works (when you speak to them) then try the Police on 101 to see if they can be moved on. If not, a civil injunction can be applied for (the cost is £308 for the application to the court).
I hope this helps? If I have answered the question would you kindly leave me a 5 star rating (at the top of your screen), any follow up questions are welcomed.