Mo,
Here is the clarification from my solicitor:
'Legally speaking, if you are renting out your property a rental income tax worth 24% of the rent has
to be declared and paid every quarter. However, not everybody declare this tax so this would be upon your prerogative. If you own several
apartments here in Spain and this is one of the main source of your income, then it would be advisable to declare the tax. But if you only
own one property here in Spain and letting out this property to a person you know then the decision should be yours whether to declare the tax or
not as most of the owners do not declare this tax .'
So that's that sorted then!
Kevin