Can anyone give any guidelines, as to what can safely be done without planning permission ? For example, I have been told that old windows can be replaced with new without permission as long as the widows are not enlarged.
Also that all interior work can be done and interior partition walls added in safety ?
I have a garage at the front of my house that just needs garage doors fitted, front and back. Could I install windows and sliding doors front and back and so turn it into additional living space without planning permission ?
Yes, Mr Blueskies, well informed estate agents have this information.

Ok, new laws regarding building,planning etc, go into the Diario da Republica, and are all available to be viewed, so that you can clearly see what the laws are and how they may affect you. (or your property)
In this case we are looking at what can be done without planning permission,
so in the Diario da Republica, 2a serie-no 206 - 23 of October 2008
under Artigo 4 Isencao de controlo previo
it lists all the work that can be done to a property without the owner having to apply to the council for permissions.
for example, things like garden perimiter walls upto 1.8 meters, land terracing walls upto 2 metres. new buildings in the garden less than 3 meters high and less than 20m2, some interior work, etc, etc
it does list lots of changes that can be made without a license or project, anyone interested in rebuilding or making changes to a property should go through info like this first.