Re: Child benefit... @AC
What you are supposed to do is tell your wife to let the DWP or whoever it is that pays child benefit that one of the bread-winners is a higher rate tax payer, so that the benefit is stopped.
No, it didn't work for me either. My wife kept saying she'd call and do it, right up to the point that our youngest child left education. She didn't want to lose the income that was under her sole control (which actually often didn't get spent on the children, but that's another story).
It's effectively you paying your wife the equivalent amount as the child benefit, but by a really, really inefficient route. And on top of that, the fact that in UK law, your tax affairs are your concern, not your spouses (and vice-verse) means that if your partner won't tell you what child benefit they receive, you're effectively guessing (with a little bit of assistance from HMRC in the self assessment process) what the amount is, with no check to say whether you are correct!
Definitely a broken system.