Hi
Your tax return would the need to include the residence section (SA109), to declare that you are not UK resident and claim personal allowances.
You would also be required to declare all of the income and capital gains arising in the UK in the tax return. Please note that you cannot use the HMRC tax return to submit the residence section.
If you have a government gateway user ID and password, you can buy a commercial tax return that includes residence and submit that version. A list of commercial tax return providers can be found at
Self Assessment commercial software suppliers
If this method is not possible, you will need to submit a paper tax return, which can be downloaded at
Self Assessment tax return forms.
Thank you