You hold them to account by going to court.
It's ridiculous to expect people to have to take an LA to Court to enforce their statutory rights. For a start a lot of the parents don't even know they have such rights, let alone the means to launch legal action against a LA that is well upholstered with tax-payer funded legal support.
LA do not make final decisions. Judges do.
LAs like to tell you their decisons are final, that you won't get anything else by complaining, that their actions were appropraite. I was told that at all three stages of my complaint against my LA. The Local Governement Ombudsman thought differently and pointed out the error of their ways to them. Again, a process that relies on a judge to overturn LA decisions is not fit for purpose.
Or are they all corrupt and intent on stealing babies too?
No, they are not intent on stealing babies - don't be silly. Adoption costs money, they don't like spending money.
But if you're asking whether they are all corrupt - yes, definitely and morally bankrupt.