She follows interventions ranging from anger management courses to drug and alcohol counselling.
The children are aged between 10 and 16 and most have been placed in the units following sentencing by the courts because they are too young to be placed in young offenders institutes.
With intensive staffing ratios and heavy security, the cost of each place is high, but if it works the benefits to society can be significant.
At one secure unit, on the outskirts of Bristol, Winifred follows 15-year-old Mitchell, who is admitted after trying to hang himself in a young offenders institute.
He was sentenced following a vicious robbery which left a younger boy hospitalised.
Mitchell blames cannabis and the wrong friends for the attack, and while locked up he works hard on addressing his behaviour.
He plans for a better life on his release but his old friends are waiting for him back home, and both his parents and staff at the secure unit worry about what will happen.