Hi Rich,

I'm halfway the project you describe so I can provide you some answers:
Yes, you will need permission to rebuild. In my case an extra difficulty is the ruïn is in PEIN (protected) area so the ayunamento also needs permission from the generalitat.

In general the change you will get permission is bigger if 1) there is at least a footprint and the ruïn is discribed in the escritura 2) you rebuild in the same size and style 3) if  you let an architect make a set of decent drawings and calculations 4) if you rebuild an almacen (rather then a house). But it also depends on the area and local rules. The ayunamento can inform you about specific regulations.

About the waiting: I'm waiting for half a year now and according to the ayunamento the end of the tunnel is in sight. I'm leaving for Spain tomorrow and hoping to pick up the paperwork this holliday (yes, I'm an optimist  ). I did presume it would take me a year to get permission so I'm still on schedule  .

Regards,
Mark