He is hard to believe. That's what I find.
He gives some interesting information. According to him he had regular contact with OG until 18 months ago. That's when they announced they had one remaining line of inquiry.
He says the Yard ' don’t want me trampling on their path'. Did they tell him that 18 months ago?
He says the Yard had 'some very good lines of inquiry to follow'. Perhaps he was giving them 'lines of inquiry' and they got fed up with it?
He thinks Madeleine was taken by a 'child-sex gang' but could still be alive. I don't know why he thinks a child sex gang would target this child when there are thousands (at least) of children who would have been much easier to take. He, like all those with 'pet' theories, doesn't give any evidence to support his belief.
He seems to be pitching for his old job back when OG stop investigating. He's not expecting them to succeed then?