Just a few questions:
1. Could you be a bit more explicit about what Sekiya found "distasteful" about the Saito version of ken?
Well, it might have been the way we were doing it.
There was a makiwara in the dojo and the Yoshinkan background of Minoru Kanetsuka sometimes showed: slow, basic training, with uncooperative ukes. There was lots of tanren uchikomi training at the makiwara. In addition, Sekiya Sensei most definitely did not possess Mito-kishitsu
in any way. By profession he had been an engineer with JAL. Personally, I do not think he 'believed' in aiki-ken, at least as an established sword art. Of course, O Sensei trained with the sword in Iwama and this was called 'aiki-ken'. This is part of established aikido doctrine, but Sekiya believed that a sword art as such was kenjutsu, like Katori and Kashima.
2. Despite Chiba's stopping Sekiya from teaching his ken in London, was there ever any influence in Chiba's own ken from Sekiya, who was after all his father in law?
I do not think so--certainly not at that time.