Perhaps you should consider doing a beginners course if only to learn some of the formal aspects of freediving- eg. recognised safety precautions, breathing exercises, training tips, etc. If you can put up with a few hours in a pool or on a line then I think you will find it worthwhile in progressing with the "larking around" discipline.
You also may need to accept that being such a new discipline "larking around" may take some time to be adopted by the existing teaching agencies. If you have some qualifications from AA, AIDA, PFI, FIT, etc, then maybe you can start to develop your own program.
How you would decide the winner in a larking around competition is probably going to be your biggest problem though.:t