You haven't really given enough information. I assume that the £51,749 is employment income and the £11,205 is PAYE deducted at source but you haven't made it clear whether that's the case or if it's more complicated than that.
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Pearce & Co - Chartered Accountant and Chartered Tax Adviser
Assuming that that is the only income to go onto the tax return:
Total income = £54,925 (£51,749 + £3,176)
Taxable income = £48,450 (after deducting the £6,475 personal allowance)
Tax liability = £11,900 (being £37,400 x 20% and £11,050 x 40%)
As you've already paid £11,205, that leaves £695 outstanding.
If you're using the HM Revenue & Customs software, then it should calculate the liability correctly. If it's saying £911 is due, then either there is something else on the tax return that you haven't mentioned or you've inputted the figures incorrectly. A liability of £911 arises, for example, if the P11d cash equivalent is entered as £3,716, instead of £3,176.
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Pearce & Co - Chartered Accountant and Chartered Tax Adviser
