Late apply for UTR and length of stays in UK

Hi HMRC Admin, I did not work in HK but I and my spouse sold property and all transactions settled and received before coming to UK. After coming to UK, I still do not work. Since I assume I am non UK resident according to guidelines, I did not registerd fo get UTR. Do I still need to get UTR to do split year and report the capital gain. The property was our only home address in HK before, no tax should be generated. My spouse involves Hong Kong employment till mid Mar and become self employment of the same company during tax year. We arrived UK by the end of Jan but his employment ceased till mid Mar 2023 . During this short period, he went back to HK and work 27 days to complete his duties. As a result, the number of days spent in UK was 39 days while the total no of our family live in UK in a rented property is 66 days till 5 April 2023. Since the days of leaving was due to his job duties, when he counted the no. of stays in UK, is it correct to deduct 27 days? Many thanks!

Hi

If you qualify for split year then you only report any foreign income for the UK part of the year Residence, Domicile and Remittance Basis Manual.
If you do not qualify then you will need to report all your foreign income to the UK Tax on foreign income  
The guidance at RDRM12150 at www.gov.uk will help you work out if split year treatment applies. 
You should also refer to this to work out your residence as this is for you to determine
 
Thank you