I think Chantelle was a decent kid with a good relationship with her mum. Just so much grief in both of them. I don't think she wanted a baby, I think she wanted the other baby back. I was surprised the counsellor didn't say this to her. I hope they are both getting some decent grief counselling.
As for Lydia...She came across as a rude, spoilt immature girl who was strangely annoyed with her mother. She said a few times how 'old' her mother had been when she had her (I think she was 37) I don't think she was prepared to listen to anyone else's POV.
As an aside, I thought the teenage mum whom Lydia visited was very sensible, mature and articulate for a 15yr old. I think the point that Lydia was missing was that although the other girl had fallen pregnant at 13, it wasn't planned. Planning to have a baby without security or support seemed to her (and everyone watching), madness.