I think the difficulties with enforcement are not that different to those which apply to domestic abuse in general. I think it's still important to officially say this isn't ok. That is an important message. I also think it will have some impact.
I agree re SureStart. The legal change shouldn't happen in isolation. I hope that there is funding for parenting courses etc. I think it is of course linked to mental health, economy etc. Like many other crimes. I agree with funding support services - but that shouldn't be an alternative to protecting children at a legal level. Children deserve that status and protection under the law that we give to adults.
I also think in a back to front way, criminalising the behaviour will generate funding for support.