https://www.gov.uk/government/news/poor-governance-at-mermaids-amounted-to-mismanagement-inquiry-reveals
tl;dr - the whole thing was a disaster, giving out dangerous outdated advice that would literally physically hurt children, including breast binding and irreversible puberty blockers
Gender questioning children deserve far better, evidence based, holistic support and care to help them through these difficult periods in their lives. Mermaids did not give it.