This is horrific and 6 years is not an appropriate sentence. If they believe, as it is suggested, that one or both of these women have mental health difficulties then they should have intervened more and earlier. Most of these dreadful stories are about children between 0 and 4 perhaps we need the state to do more and have more powers to intervene. I didn't realise you could refuse help from social services if they were concerned.
It's all very well having checks available for babies and toddlers but if you are not required to attend perhaps they are pointless. Would anyone really go to their child's one year review if they knew their child wasn't well cared for or was abused? Surely if these things were compulsory and followed up by SS if you failed to attend it would help children's services to flag up concerns. How many more of these children are there around the country that the authorities aren't even aware of?