Notes on verification

Well-documented by multiple independent sources including the Science Museum, GOSH, Roald Dahl Museum/estate, and Sturrock's biography, all consistent on the facts of the collaboration and invention. [cascade flags: wikipedia_dropped_other_sources_exist | tier=silver indep_score=0.925 clusters=2 claim_tier=notable | framework convergence=partial (upstreams: Great Ormond Street Hospital archives, Science Museum collection records, Donald Sturrock biography of Roald Dahl) — publishers independent, evidence may not be | kind=attributed eligibility=high]