Single parents on a good income have always got zip extra help - but really, why should we? Used to get CTC, which I didn't turn down obviously, but I never understood why anyone would give benefits to people on incomes as high as £55k.
The concept of a higher rate tax band IME is unfair by definition. Because we have different tax rates that kick in at particular earnings thresholds, if you're just over that threshold you're not a lot better off than if you're underneath. Peg CB to it and it's just another income stream that cuts off. Whatever the middle-income version of the 'poverty trap' is, that's it. 'Middle-income trap'?. I worked out recently that if my income halved, my take-home pay (with CB added back) would only go down by a third. I'd love a flat income tax rate but as it would be shouted down as 'the tory government looking after their rich mates' it's unlikely to happen. :)
As for working fewer hours to keep qualifying for CB, I don't think that's a wise move. My DB working in a branch of the civil service once turned down the chance of promotion because (quote) 'I won't get overtime any more and I'll be worse off'. 20 years on he's stuck in the same job on the same payscale, whereas if he'd taken the promotion opportunity he'd probably be on double the salary by now, even with the overtime.