rottenmummy, haven't had time to read the other posts so apologies if I'm repeating.
I have a 4yo dd and she can be rather annoying, challenging, driving me up the wall 24/7, wishing she came with an off button... I have turned from a rather reasonable person to this shouting mad mean mummy who I don't recognise!
I also have a 2yo ds who has now started pushing and hitting, partially due to the 'lovely' role model his sister is portraying...
Lately what I have started doing though is to totally ignore her when she gets one of her over the top moments (obviously not if she tries wandering off in the street in a mope of course) and also working on developing selective hearing... I only hear her if she speaks nicely, clearly etc. Same time I have to make sure she has actually eaten well because if she hasn't... it seems to worsen her behaviour exponentially!
And one more thing I did a couple of days ago was snuggle up with her after school when ds was still at nursery and asked her whether she enjoys her time with just mummy and NO little brother, which was answered with a resounding YES. Seems like she needed that acknowledged instead of just spending 'quality' time with her she needed to hear/be told that it's her time.
Wondering, has your dd started reception yet? My dd's behaviour got drastically worse once she started reception. Teacher reckons it's because they have to be 'nice' at school and feel at liberty to act up at home...
Not sure whether I'm making sense but at least you know you're not alone with your troubles