Wow, absolutely didn't know that, this drove me crazy in a number of situations. I never use the object corner icons nor was I aware I could set the unit to other metrics units. Thank you for your enlightment, Puybaret.
Simple solution then for a problem which seemed complicated [:)]
http://imgbox.com/LA70jGrD
This looks perfect now! I will have to redo a number of lights now, will keep me busy the next couple of hours [;)]