There is a large area on the map described with the abbreviaton ZPAV. Probably a daft question but could this mean Paved area?. It is not paved but is simply tonnes of theora but if classed as a paved area, might affect the catastral value

When we moved in we were not on the castral and had to pay to have house put on. The architect explained to us that anything paved or cemented, even outside the walls of the main property but on our deeds counted as urban and would have a higher castral and that she had to submit maps showing which areas around the house were cemented or paved, anything outside the paved area was classed as agricultural. It turned out the agricultural land was on the castral but the tax was so low that the townhall had never bothered collecting it. We now have 2 bills one for the land which is minimal and one for the house and all the paved/cement area we own.

Many thanks, flotsum and everyone else who provided valuable info. I now have a good idea as to why my IBI is as it is. ( A part of it that, according to the catastral website, my property size is about 20% larger than the others in our area). I think there is scope for an appeal which might reduce it by about 75 -100 euros a year. What I now have to decide is whether it is worth the costs that might be involved (obviously depends on how long we will live here) and whether any inspection by the authorities might uncover something detrimental (that I was unaware of). or should just let sleeping dogs lie.