But equally, one could argue that Art 16(7) means that if the flight manual says that it must be carried on the aircraft, then it must.
A thousand letters to the CAA requesting an alleviation from the aforementioned article would likely result in a rule change to prevent the 6% profit margin being eroded by overtime payments.
Since most of the POH emergency checklists also include an expanded section with additional detail, how is a pilot going to be able to consult it during an inflight problem/emergency if it is sitting on the flying club shelf?
I would suggest that your typical PPL is going to have a lot more on his mind than thumbing through the expanded QRH during single pilot ops when something untoward occurs. Especially in that either an autopilot won't be fitted or whatever is causing the need for the POH will have probably rendered it u/s.
While the theory of the POH on board is perhaps sound, in practice it is less so, particularly in single pilot private ops. In my experience, the only time I will reach for the POH (FCOM in my case) after using the ECAM or QRH is if I have time (as it is not an insignificant tome - neither is it small on a C172)
and the other pilot is concentrating on the "Aviate" part.