thatsnot I'm going to say this, and it's not going to be popular, but I feel it needs to be said. You need to get past this concern about whether or not he has a criminal record. So what if he gets a criminal record?? He's been warned by the police to stop, and he hasn't. IT'S HIS FAULT IF HE GETS A CRIMINAL RECORD BECAUSE HE IS DOING SOMETHING ILLEGAL!!!! He will continue to harass you because he can. Because he knows you won't press charges. He's counting on it.
I'm sorry to be quite blunt here, but this is where you need to steel yourself and put your foot down and press charges. Nothing else is going to work.
And if you keep ringing the police about it, but refuse to press charges, then it weakens your position for an injunction greatly. And if you keep ringing the police about the harassment, but then you offer to take him to work, it weakens your position for an injunction.
This is where you need to take a stand. Make the break now. Press charges. There is domestic abuse going on here. The injunction won't take £2k - you need to find a solicitor that will sort out the legal aid for you, as you certainly must qualify! ASK the domestic abuse personnel at the police to help you with this. ASK women's aid to help you with this.
But you MUST stop worrying about him. You MUST stop worrying about how a criminal record will affect his career. That's HIS lookout. Can't you see that he is not worried about it, because he thinks he can walk all over you and you won't press charges?? STOP PROTECTING HIM!
This is where you show your dcs that you don't have to tolerate this kind of behaviour. They will understand and they will appreciate that you are putting your safety (and their safety) first. It will reassure them - if the police arrest him, your kids will see that their dad cannot simply do whatever he wants to them, that he has to answer to the law. It will empower both you and them.
I say this not only because I've worked in law enforcement (and see, I've still been in domestic situations - it happens to loads of us, so if embarrassment is holding you back, please don't let it!) and seen it from the legal side, but I've seen from the side of the domestic abuse victim what a difference a strong police presence makes in these situations.