Taxation in Spain seems to be a nightmare. There are so many different taxes based on various valuations and the onus is on the owner to declare it all. Not only that but the whole system is in a state of flux as Europe are putting pressure on Spain to treat all EU citizens the same.
I have been looking through this site and found a thread about taxes a while ago. It seems someone has written a guide for £20 for filling in tax returns etc. I don't know how good it is as I haven't bought one yet but it might be worth an investment. See link below.
http://www.payingtaxesinspain.pwp.blueyonder.co.uk/3.html
Even if you know how to fill in the return you will still have to get the forms and presumably make the payment.
GVA have quoted 350 euros for tax return for one person and 500 euros for two owners. I assume they oversee the paying of the taxes on your behalf etc.
Does anyone have a value for IBI tax as I haven't seen mine yet?
Also does anyone know what the valor catastral of the property is?