CAO 82.3 8.5
"8.5 In the case of a pilot operating an aeroplane having a maximum take-off weight of
5 700 kg or less employed in a regular public transport operation, the requirement that
the pilot must have the relevant qualifications set out in Appendix 4 applies only if the
operation involves the carriage of passengers."
I don't see how they develop a grey area out of that?