Delta T. Yes provided that the passenger does not pay for the privilege.
The only definitive statement is the ANO. There is no such thing as a "trial lesson" its either a "Lesson" or it isn't. If any instruction is given and that may not even involve handling the controls, then it could be classed as a lesson.
At the end of the day one just has to be sensible. If you charge someone to fly and they receive no instruction it is public transport.