By default, the UK taxes an individual's world-wide income and capital gains on the 'arising basis'.
This means that the income / gain is taxable in the tax year in which it arises.
Some individual's who are resident in the UK but not domiciled in the UK, can elect to use the 'remittance basis', instead of the arising basis,
although this option does not suit everyone.
Everyone who is resident and domiciled in the UK, can only be taxed using the arising basis.
If you are not claiming the remittance basis, then being domiciled or not domiciled in the UK, will not alter your tax liability.
Have a look at section 9 of RDR1 (Residence, domicile and the remittance basis: RDR1
You can contact HMRC to correct your tax return, by writing to
H.M. Revenue and Customs
telephone 0300 200 3310 or use the webchat facility at Self Assessment: general enquiries