“child-sensitive age-assessment procedures, which should only be carried out if there are serious doubts about a person’s age, and which should always be carried out in the best interests of the child, and be subject to independent monitoring; the development of a single model of age assessment in Europe, based on the presumption that the person is a minor; systematic application of the margin of error in favour of the person concerned, so that the lowest age in the margin determined by the assessment is recorded as the person’s age; and access to effective remedies.”