On the contrary;if you read Dr.Ferguson's statements he urged Sheila to continue treatment on the NHS. I also find it unlikely that he would not have informed social services at the first opportunity if he believed Sheila to be capable of harming the boys.
At least the teacher/s at the twins school put their feelers out to the social services,,which was more in this day and age that they did for poor Daniel Pelka when they saw him rummaging in the bin for food.
The boys were being neglected,Steve.Getting their own breakfasts,dressing themselves and going without a wash. Their drawings reflected their home life,yet nobody picked up on that alone,which should have happened because there was no such thing as PC in those days,but sadly the authorities were as blind then as they are now.