You can search for your nearest service here www.womensaid.org.uk/domestic-abuse-directory/
The email address is [email protected] but as there can be a delay of 5 working days before you receive a reply that won't be much good to you now, although it won't hurt to email a brief account of what's gone on in the past few hours when you have time.
Having read your other thread and your subsequent response here, it seems that the police may not have logged your call as being related to domestic abuse as it appears that your primary concern was that your h didn't harm himself rather than fear that he'd harm you.
I advocate for victims to stay in their own homes, particularly where there are dc who need stability after witnessing violence or a parent acting out, and it seems to me that you may be best advised to stay put, wait to see how he presents when he returns to your home, and have your phone primed to call 999 if you have reason to suppose that he may harm you.
In case anyone forms the view that this advice is somewhat gung-ho and may place you at risk, it should be possible for you to gauge his mood from an upstairs window while he's standing on the doorstep unable to gain access because a) he hasn't got his keys and b) the entry door is securely locked. If you have any fear that he smash his way in, call 999 and lock yourself in the bathroom, loo, or any room that has a lock on the door or suffiicient furniture to form a barricade, until the police arrive.
I also suggest you get back to the police and ask to be referred to an officer who works in your regional police authority's Domestic Violence Unit as you are concerned that he may visit the damage he inflicted on the worktop by stabbing it with a knife on you/your dc.
The net result of this should be that you will have sufficient cause to apply for an occupation order which will keep him out of your home and for a non-molestation order to keep him away from you when you are out and about.
As I've said, at the moment it appears that the concern is one of him self-harming whereas the priority should be to keep you safe from violence from him.
Alternatively, you could cram your car to the brim, set off for your grandad's after your dc has had breakfast, make the necessary calls to the police, and search for your nearest Women's Aid/Refuge service.
Does he have any friends/relatives he could stay with?