Overseas Landlord / Double Taxation

I have been an overseas landlord since 2011 and rent out a small cottage in Scotland. For the last few years I have been required to use commercial software for my online tax returns. I tried a different software provider this year, although that may not be relevant if the forms have changed anyway. I do not recall requesting one but I received a paper tax return this year. Sadly it arrived about a week before the October 31 deadline, so I could not have returned it to UK in time. I received SA100, SA105 and SA109. When filling in the online form SA109, page RR 2 I did not know if I needed to fill in box 22. Indeed I did not know how to do this as there seemed to be no way to access the HS304 claim form using the commercial software. I emailed the software company about this but I had no reply. The paper tax return did not include the HS304 claim form, so does that mean I can leave box 22 blank? I live full time in Croatia and do not pay tax as the cottage rental is my only income and is well below the personal allowance.

Hi

Box 22 should be left blank in your scenario as income from UK property is not exempt under double taxation treaties.
Even with the completion of the HS204, this income is still taxable in the UK. see guidance at Tax on your UK income if you live abroad

Thank you