Seems our posts crossed Rich.
Clearly within France what you need to do if you hold an AOC is scrap it. Save the costs! Allow your customers to hire the aircraft and pilot seperately and you're away.
The last comment above mine that says 'if there's an incident you wouldn't make the adjustment' highlights the 'dodgy' path you're probably following.
A few questions do spring to mind though.
For the very first yacht viewing trip you ever did. How did the potential purchasers know you had access to another operators aircraft and that you could fly it?????
Were you asked or did you offer?
For subsequent trips are you surprised each time you're asked or do you offer/advertise the aerial viewing service?
How do you decide how much to 'indirectly' charge for your piloting time?
As you provide a freelance piloting service to those that hire an aircraft and then hire you, what liability insurance do you have? Who pays if either the aircraft is damaged or the passengers are injured?
Does the aerial viewing ever clinch the sale? If so, are you not making a profit/income out of that flight
(Hire or reward is different to simply recieving hard cash as payment for the actual flight costs).
It would of course be a different set of circumstances if your employer actually owned the aircraft, and the potential yacht buyers were given the trip for free.
End of the day it's YOUR licence and reputation if things go wrong.
FWIW thats a major fact I'd consider if my long term ambition was a full time flying career. (Apologies if my assumption that you are relatively low hours and trying to get some flying whilst awaiting a 'break' are incorrect.)