"Own a property as a non-resident? Unfortunately, you have to pay income tax."
In Spain, if you have a property it is automatically considered as a type of income and all owners named on the Title Deed should present an annual declaration for each property owned. Most owners are still unaware of this.
It is important to understand that this is an Income Tax on your property and is separate from, and in addition to, the Local Tax/IBI/SUMA (which is an annual payment on the actual bricks and mortar). It does not relate to income in terms of your wages or your pensions, but only to property ownership." (spanish tax information)
I think we were quite lucky with our Solicitor charges last year as the few I just checked on the web are definately higher - but still would be an option as fines are quoted as up to 200 euro's