There's a Children's Rights Impact Assessment which looks into the secrecy aspect that you might find helpful Libby55.
You'll find it here secureservercdn.net/160.153.137.99/hjn.a49.myftpupload.com/wp-content/uploads/2019/01/Childrens-Rights-Impact-Assessment-by-Women-and-Girls-in-Scotland.pdf
Pages 20 to 24 address the secrecy aspect. Here is an excerpt:
Making recommendations in regard to information sharing with parents without taking into account the differing capacities between older and younger children, or children with disabilities or additional learning needs, may contravene the principle of article 5.
The guidance [LGBT Youth Scotland Guidance] also mentions the potential “risk” posed by the child’s parents in relation to information sharing.
If a school believes that a child is at risk from their parents, for any reason, then they should take action in line with local child protection procedures. While ‘inadvertent’ disclosure should always be avoided, in terms of information sharing, the primary consideration must be the safety and wellbeing of the young person, and vital to this is the facilitation of a support network, particularly when a lack of parental support is a known risk factor.
In the absence of any child protection issues, it is questionable that it would ever be in a younger child’s best interests to withhold information regarding a trans disclosure from their parents. In which case, the directive to seek consent from the child may be misplaced, as “consent should only be sought when the individual has a real choice over whether the information should be shared”.
In line with article 5 and the evolving capacities of the child, it should be recognised that older children and young people will begin to exercise their rights (for example, to privacy) on their own behalf. This stage, during which young people are still dependent and in need of protection but are increasingly autonomous and competent to exercise their own rights, is recognised as “perhaps the most difficult and controversial issue in children’s rights.”
Even with this in mind, and with no immediate wellbeing concerns, in the first instance, information sharing with parents by the young person themselves should be encouraged, in order to assist parents to fulfil their responsibilities to their child as advised by article 18 and to facilitate a support network for the young person. If there are reasons why parents may not be best placed to support their child, then investigation of alternative support for the young person should encouraged, such as from a grandparent.
Article 18 and child protection guidance underscore the importance of parental involvement, as parents have the primary role in safeguarding and protecting their children’s best interests and wellbeing. Routine maintenance of confidentiality from parents, who may be a crucial source of support, without further investigation with regards to wellbeing or differentiation on the basis of evolving capacities, may contravene article 18.