As the attached screen shot I have one polygon layer (black) which has some missing polygons and another layer (red) which contains these polygons. Both were created from same shapefile originally and they are multipoint polygons

**What i'm trying to do**

Select polygons from complete layer (red) where gaps in target layer (black).

**What I've tried**

Using Vector / Research tools / Select by location. 
Select all the complete layer then remove from selection based on the `overlap` selection. This results in some but not all.

I then tried 

Select all the complete layer then remove from selection based on the `intersection` selection. This results everything getting selected.

I was trying to find documentation on the precision function within the select by location to see if this might help. In my head overlap is the right function as i want to remove all the polygons that overlap one another which should leave just the mismatches which are my gaps. 

EDIT; There's some useful reference on the Geometry predicate here ; https://gis.stackexchange.com/questions/217444/documentation-join-attributes-by-location-qgis-2-18. Have now additionally tried using the `contains` predicate but this also selects all. 

[![Screen shot of problem][1]][1]


  [1]: https://i.sstatic.net/03SUj.png