Tax returns

Royalty tax ?

Not sure what this is.

If you mean SUMA or NRT, use a tax gestor or Assessoria - explain your circumstances and pay, before they chase you.

If you became Residents in 2019, you are into Spanish income tax, so you need a gestor/assessoria anyway.

Ok thanks for the info

"If you became Residents in 2019, you are into Spanish income tax, so you need a gestor/assessoria anyway"

Not true: if your affairs are simple (pension income, no rental income, no sale of assets abroad etc) you can do it yourself !