Hi Liz,
I think we are in the same boat as you!
We were told that we should get a new updated escitura, as the one we have at the moment shows a casa in “very bad condition” and that the tax is the increase minus the amount you have paid for renovation works.
Hope this helps, I´d be very interested in any info you find out, although we are most definetly not planning on moving for the forseeable future!!
Heather