I have been informed from my Accountants in Spain :
Spanish tax office distinguish between two groups of Non-Resident:
1-RESIDENTS in EU, Norway and Iceland.
2-RESIDENTS in any other country (British would be in this group from 1st of January 2021).
So from 1st Jan 2021 I will pay 24% tax across the board on all Income generated in Spain.
"You can not take into account any spending. Not even commissions of Airbnb. Nothing at all."
My Accountant states this will result in approximately 2.5 time the tax as I pay today. 😞