[Ghoulish Delight]

I believe the generally accepted excplanation for Obi-Wan's lack of droid knowledge is that he's a big fat liar. He does, after all, lie initially about Luke's father. So why not lie about knowing droids?

I've decided that once Anikin is saved from the Dark Side by Luke, he's so wracked by guilt at his failing that, in a tribute to his late masters and trainers Obi-Wan and Qui-Gon, he affects a British accent. It's touching, really.