I never understood Hendrik to make the claim that Yik Kam WCK was the "true original" WCK (unlike others), only that on the Red Boats the SLT was originally one set.
It seemed likely that it was Wong Wah Bo that choreographed the three sets (SLT, CK, BJ) considering that his two students, Leung Jan and Fok Bo Cheung, both subsequently taught the same three sets.
IMO WCK existed on the Red Boats, and that there existed several different types of curriculum for teaching it also on the Red Boat (one form, three forms, san sik).