Telling you to "calm down" after responding to being TOLD what you WILL do next week is not the mindset of a man wanting to change.
EVEN IF he says he'll go to Harley Street (really? will he? surely they're booked up months and months in advance if they're that fantastic...?)
I truly do not believe you should be going on this trip. You will be totally at his mercy, with the children, far from home and any immediate support network.
You are exceptionally vulnerable at the moment; putting yourself at further risk is not safe. Simple as that. He will use that time away to weedle his way further back in to your mind, in to your life. It'll work too, because you're so desperate for the "old" H back.
The totally awful realisation you still need to come to is that the "old" H was a massive mask. A trick. A lure. Who he is now is who he genuinely is. He HAD to be "nice, warm, safe" for you to stay in a relationship with him, to depend on him, to "fall in love" with him.... he then started letting the mask slip, but not enough for you to explicitly notice until the day he knew you were so ground down that you'd struggle to leave. Then he knocked you unconscious.
He was wrong though. You've left.... that's the one thing that's now totally freaked him out and he's trying EVERYthing he knows and more, to get you back.
Tread extremely carefully. My very strong advice is to stay away; have contact in a Centre and go to the Freedom Programme until you can see what has been happening. That may take one or two runs of the FP, by the way, seeing as it's so hard to be honest with ourselves when we wake up to what's been happening.
PLEASE be very, very careful and be honest with yourself. If you go away in half term and he does something, how will you get help and get safe?
Even if he doesn't do anything, he'll be in the "honeymoon period" section of the Power Wheel to lure you back in. They're all the same. Abusers, that is - they're textbook.