So Grandma had Tia's mum when she was just 15???
As for Hazell, I think they got his age the wrong way round. 37? 73 more like. He looks totally shattered. One thing I'm confused about is that the stepdad said when Tia left Grandma's house, Hazell was hoovering and couldn't hear where she said she was going. Who did she tell she was going to Croydon then?
The stepdad obviously talked to Hazell in order to have that information. If he was hoovering when she left then it's possible the neighbour did see Tia leave on her own - but once again, it means Hazell lied about walking her to the tram station and inventing additional details about not going with her because it would be 'too busy'.
I imagine the police will have interrogated him about all the inconsistencies in his stories. Although maybe he lied to his dad in case his dad asked why he let her go on her own? But... she seems to have gone out shopping on her own a lot, so why he'd feel the need to pretend he'd walked her to the station is a mystery.