Hi chrissiehope,
"I find it useful if I'm not going to be in Spain before the tax is due"..............
The Non-resident tax can be paid any time throughout the year, and is based on the previous years numbers...............one would hope you would manage at least one trip a year.....
I know the Digital Signature was a pet project of yours and thank you for the FAQ on the subject.
From my angle , although I got The Signature , I've not had any real use for it.........If I miss any of the "window payment " taxes like IBI.....just pop into the office , get revised amount (fine) and pay in the Bank. Was two months late last year and had a 4euro fine.....
UNIX is basically a simple operating system, but you have to be a genius to understand the simplicity.