Whether or not Catalonia goes independent is a different matter but there will be growing friction between Madrid and Catalonia. Will this impact on the Spanish economy? Will it hit Spanish house prices?
Once Brexit settles down I think that UK investors will return to the Spanish market and help to pick up some of the slack. I read just a few months ago that there is still a lot of unsold stock on Spanish bank loan books as a consequence of mortgage defaults after the 2008 financial crisis began. This will not help prices in the short to medium term.