We have heard that the PP is against all building and will, if necessary, revoke building licences that have been granted before the elections. Is that true?

No. That rumour was circulated during the last elections.  In the past, illegal building licenses were granted to both bring much needed money into town hall coffers (remember nobody pays serious rates in Spain) and as favours to buy votes at election time. This latter practice proved to be a double-edged sword for everybody since nobody had any recourse when their neighbour built something illegal.

When one resident filed a complaint in the town hall about an illegal second-floor building which blocked their view, they were told that “no one has a right to a view”.  Whatever the situation in the past, since the corruption scandals throughout Spain related to construction have come to light, these practices have been stopped.  Mayors simply no longer have the ability to issue building licenses which do not conform to strict laws. They can be fined or taken to court if they do not.

If your building licence requests are reasonable and conform to the law, there will be no reason to refuse them.