Turning catalogues, glossaries, and lineage tools into something regulators will actually trust. Most Financial Services organisations invest heavily in data catalogues, glossaries, and lineage tools: yet still struggle to satisfy regulators when asked to explain where data comes from, what it means, and how decisions were made over time. This article focuses on governance and metadata that actually survive Prudential Regulation Authority’s (PRA) and Financial Conduct Authority (FCA) scrutiny. It sets out a practical model for connecting semantics, lineage, rules, and accountability, so regulated firms can move beyond decorative governance and confidently explain historical outcomes with evidence, not anecdotes.