The Government should designate an independent body, such as Ofsted to investigate the reasons of any nursery/school asking for a child's relocation. This shouldn't be done without this body's approval and must include cases where parents are working in the same institution as their child studies.
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The off-rolling is an issue when the institution in case does it for it's own benefit and not for the child's best interest. To prevent any injustice to be done to a child or parent a designated governing body should hold the decision, not the institution's management.
To prevent the institution verbally convincing a parent to move their child, a form that questions that should be required to be completed by the parent when relocating schools/nurseries and analysed by the same governing body.