julia Beesley

Hi,
I am a Spanish national, resident and working in UK for over 30 years.
I am applying for a certificate of fiscal residency and I am struggling finding answers for some of the questions in the form.
I need a certificate to declare an income from rent of my flat in Spain and I need to find out:
Which article of the county's double taxation agreement covers the income in this request?
Do the subject to tax provisions apply to this foreign income?
Many thanks