I registered for self-assessment as I now earn just over £50k a year (after pension has been accounted for) and we still receive child benefit.
I've just tried to do the self-assessment online, and I must be doing something wrong as it is telling me I need to pay back around £45 when I know (looking at the government calculator!) it should be around £380.
I pay £180 over the year to charity via direct debit and ticked the gift aid box when I set it up. It seems the £45 charge is coming from where I've put my gift-aid in (if I take that out it goes down to 0) but I don't want to submit knowing that I need to pay quite a lot more than that!