In HoleBASE SI I've not found a way to display on the map only the desired exploratory holes (e.g. a location group).I am aware this is possible in civils extension for holebase but I want to be able to do this in Holebase - easier to produce plans in Holebase with background mapping / background 1:50,000 geology etc.
Thanks for asking about this, you need to use location theming and then turn on the locations from the Map Legend. See the article below for location theming help:
In the Map Legend go to Location Groups>Groups, and turn on your group.