How do you sell a flight without making it public transport?
(3) Subject to the provisions of this article and articles 158 to 163, an aircraft in flight shall for the purposes of this Order be deemed to fly for the purposes of public transport:
(a) if valuable consideration is given or promised for the carriage of passengers or cargo in the aircraft on that flight;
You can't do public transport in a Microlight or even rent it on a Permit.