I need to select which MULTIPLE attributes to join in a QGIS model. It allows me to do this in the interface (Properties-->Join) but not in the QGIS Model version of Join by Attribute.
So I want the match to be by LOTPLAN and the then some attributes joined and others not.

Properties > Joinfunction in your modeler. You can add additional fields to the script. – Joseph Aug 01 '16 at 13:30