Assessment of Gillick competence requires an examination of how the child deals with the process of making a decision based on an analysis of the child's ability to understand and assess risks. It is a high test of competence that is more difficult to satisfy the more complex the treatment and its outcomes become.
A person has to be competent to do the assessment - ie guidelines refer to doctor or nurse practitioner. Was it a nurse practioner here? Were they competent to do the assessment, and was the assessment competent? the guidelines clearly state that this is not something to be use to just override a parent's wishes - this is a quote from the guidelines:
Gillick competence is a functional ability to make a decision. It is task specific so more complex procedures require greater levels of competence.
[...] a health professional has to decide whether the child is or is not competent to make that particular decision. It is not just an ability to choose where the child recognizes that there is a choice to be made and is willing to make it. Rather it is an ability to understand, where the child must recognize that there is a choice to be made and that choices have consequences and they must be willing, able and mature enough to make that choice
Assessment of Gillick competence requires an examination of how the child deals with the process of making a decision based on an analysis of the child's ability to understand and assess risks. It is a high test of competence that is more difficult to satisfy the more complex the treatment and its outcomes become. To date no court has found a child in need of life sustaining treatment competent to refuse that treatment. [..]
Sufficient time for the assessment must be allowed by the health professional who needs to be satisfied that a child has fully understood the nature and consequences of the [proposed treatment] and is mature enough to take account of broader health and social factors when making their decision
The right to decide on competence must not be used as a license to disregard the wishes of parents whenever the health professional finds it convenient to do so. Health professionals who behave in this way would be failing to discharge their professional responsibilities and could expect to be disciplined by their professional body.