As far as the PhD plagiarism goes, I'm surprised there is not more focus on Liverpool John Moores rather than Cambridge, as they awarded the PhD. I wouldn't expect subsequent employers to check the content, though they might verify that it actually existed. (From the Guardian yesterday, "Cambridge initially came to Arday’s defence... It said it had passed complaints on to Liverpool John Moores University").
For the outlandish claims of marathons etc., I'm not clear whether they were on his application, though I assume they would have been. They would definitely be ringing alarm bells. As for the other things about not speaking till 11 and not reading/writing till 18, I'm sure that happens to some people, but to then go on to get a degree, a PhD and a professorship? Hmm.
And from his own comments (quote from BBC): "The Times reported Arday defended himself by arguing that he had not received adequate supervision during his PhD given his autism and "learning disabilities".
In an interview with the Times, Arday said that he could not afford a proofreader to catch mistakes when he started out in academia." Yes, the uni should be supervising him, but frankly, if you have learning disabilities and also need a paid proofreader, how on earth are you PhD material? A PhD is supposed to produce a rigorous academic thesis, and if you are not capable of doing that you shouldn't be accepted for a PhD in the first place, and you certainly shouldn't be awarded one for a subpar thesis.