hmmmm.... not seeing any aggro in any of the previous posts Mark1234. I too agree with previous posters; the hours can only be logged by one of the PPL's on-board, usually the licensed pilot occupying the left-hand or command seat. The scenario you portray meets the definition of neither Dual nor Instruction.
With regard the right-hand seat endorsement... I've never heard of that one either, although I think you may find the regulator would prefer the aircraft be flown from the seat with the most flight instruments in front of it, if for no other reason than to preclude the possibility of error caused by parallax when viewed from the more distant seat -something instructors and others trained to fly from the right-hand seat without a full suite of flight instruments before them are specifically trained to compensate for, let alone the differences of actually flying from the right, particularly in the landing phase.
Recording the hours is quite OK -in the NZ logbooks there is a column at the extreme right of the page for analysis or recording of flight times that do not count towards any logbook totals at all. I imagine there would be similar in Australian logbooks also.