Colditz - emotionally, the more time they have a parent around, the better.
OP - "I see what you're saying, but how then? How do I make them stop? I read books, I've been on courses..."
Stop trying! Do things that mean that they don't get bickery, and accept that it is part of life when it does happen. When they are physically violent, then you need to just calmly, and lovingly (because children play up more if they think you don't love them when they're unpleasant) hold their hands and tell them that hitting is not acceptable.
Don't think that I think I'm wonderful and do this all the time. I'm shit at it - I'm always yelling at them. But I try to do it the right way, and when I can be calm, and involved and engaged with them they behave better and bicker less. And we get involved in lots of activities where they can learn to co-operate. Also, I try and give them tools other than hitting to deal with things, like reminding them that they can try to sort things out with words, and come to me if that doesn't work. Don't expect them to stop bickering completley though, or learn not to hit overnight. It takes time and patience - you have a vested interest in teaching them these things, a childminder or nursery worker, however well-meaning, does not.
"And DH and I both wanted to have children, how does that mean it all comes down to me to do all the practical hands on parenting?"
You tell me! It's your family - if you're unhappy with the balance of work , t hen you need to talk to your DH about it. For us, DH takes over the minute he gets in the door, and on his days off he's the main parent as far as the children are concerned.
"I'm not asking someone else to parent for me, I would just like a break and a bit more in my life than just parenting."
But you're saying you want to go out to work full-time! Doesnt' leave much time for parenting. Be creative - find ways to do things other than parenting at other times. Go out to the gym when your husband gets home. Go out for drinks with your friends in the evenings. Go out for coffee with them at the weekend.
"I don't think wanting to be a mother and being able to work/earn money/widen my horizons means that I am "running away" from my parental responsibilities? "
I don't either, but, like I just said, you're talking about full time. And not because you want to widen your horizons, but because you don't want to be with your children over the summer holidays. I work part time, but I do it when DH or my mum is around. I only manage 3 or 4 hours a week, but that, coupled with my 'me time' I ensure I schedule in, is more than enough.
@ everyone else - I bloody hate this 'mothers who decide to stay at home while they're children are younger must be martyrs' thing. Guilty conscience making you be nasty maybe?