Hi, my husband falls into the 'child benefit high earning' bracket for tax yr 2013/2014 so I registered to do self assessments. Appreciate, as a result of this, we need to do a return for y/e 2012/2013 (although his earnings were under limit to receive child benefit for that tax year) which we've just done online & it comes back as we owe tax. Just a bit miffed as in July 2013 HMRC wrote to DH stating they've reviewed his income for 2012/13 and due to a benefit in kind of £1k he has underpaid tax of £400.60 so they issued a new tax code to collect this shortfall. In the section of the tax return for underpaid/overpaid tax for 2012/13 we initially put the £400.60 but it came up that he owed £800 tax (payable by 31/1/14) We then amended this under paid amount to £0 (as surely he's already paid that through his amended tax code this year) & it came back as owing £400.00 by 31/1/14. So how can he still have underpaid tax for 2012/13 if they've already reviewed & amended his code??? Feel like we've opened a can of worms we could have done without particularly as they want it back in 1 go by end Jan!! Thank you