Just out of curiosity does the Jan de Jong/Hans de jong aikido schools give out certificates in "Yoseikan Aikido"? I am pretty sure the only Yoseikan school recognized by the Mochizuki family in Perth is Roy Hebdens Yoseikan Budo Dojo.
I can not comment on the activities of "Jan de Jong Martial Arts Fitness" and I think it best that I don't. I will say my 6th, 5th, and 4th kyu grades and certificates were signed by Jan.
As for me, under Sensei Hans, he got his shodan from Yoshi, and he got his 6th dan from Mochizuki Kancho. My 3rd and 2nd kyu certificates are from Hans. I will never get a shodan from Hans, I don't think he would ever offer one, and I would never ask for one.
The term Yoseikan does not only belong to the current Mochizuki family. Also, this fact does not stop our Aikido being Yoseikan Aikido. Lets just say I am not going to be doing a Gary Bennett and appointing myself a 10th dan, EVER!