Moving to England with your family

The way we did it worked for us, but it wasn't easy.
I came over to England first, looked for work, a house, schools and did most of the paperwork required. Sorted my NI number out, banking, driving license etc, during which time my wife and kids sold up and prepared for their move some 5 months later.
There were some benefits doing it this way. As an example, I more or less knew the ropes for when they got here, and I could decide better what to ship over and what to sell/abandon/give away from our home.
My kids settled very easily, and within a week at school, had friends and appeared well settled. They generally excelled with the schoolwork, and still have the same friends 3 years later.
In my opinion, bring over as little as possible, apart from essentials, be prepared to start life over, but make it as easy as possible for yourselves as it is a huge adjustment.
I used Freecycle a lot here, and it helped a great deal until we could buy new items. Then we moved those items on to someone else.
It all worked well in the end, and in retrospect, I would do it the same way again, just with more money!