I'm obviously not a lawyer, but I'm about to do my first Part 61 "proficiency check" so I've spent a while trying to get my head around the rules and that's how I interpret 61.875.
Although then, 61.880 4B states:
If the holder is taken to have a valid instrument proficiency check for the relevant aircraft only because of the holder’s participation in an operator’s training and checking system, the check is taken to be valid only for operations conducted by the operator.
So if you haven't done a proper "proficiency check" in the past year as opposed to your company C&T you'll need to do that too if you want to fly privately, cheers CASA.
As far as I can tell, the requirement for equipment-specific experience for GNSS approaches has finally been killed off though.