Self employment tax when living overseas

Hi there, I live and pay tax in the USA but do self employed work for UK companies. I’ve just come to file my taxes myself for the first time (I had an accountant do it for me before, but he’s since retired), and despite ticking the box saying I’m not a UK resident, the calculation comes to me owing some £20,000. Should I change my answer to the question about having >£1000 turnover from ‘yes’ to ‘no’? Otherwise, how else do I submit the form online showing that I pay taxes in the USA and so don’t owe any in the uk? Thanks so much for your help!

Hi MummyTown,
As you are not resident in the United Kingdom in the tax year that you generated the self employment income, it is not taxable in the UK.
You do not need to declare the self employment income in the UK.
You should be declaring the self employment income in the USA, as foreign self employment income and paying the tax to the IRS.
You will need to amend the tax return you have submitted to the UK.
For a more detailed reply, you would need to contact our Self Assesment helpline. 
Self Assessment: general enquiries
Thank you.