OP, the police would most certainly believe you. You are trying to divorce an abusive man that terrorises his family, who has guns in the house. The fact they are licensed does NOT make this ok.
You can tell them the name of your solicitor.
They would be most concerned to know that he has licensed guns in the house and is an abuser.
This is worth using to have him removed from the house.
You have no fear of drama.
You need to play hardball with this man.
You clearly love your children.
But believe me their lives and childhood has been ruined by this man.
Involving the police, informing them of how you all are fearful of the guns and knives would help you.
Your sons would be able to verify their fear of him.
Tell your solicitor you want him out of the house now. Removed.