Author: Oliver Wakefield-Smith, Founder Digital Signet. Reviewed against DfE Sustainability Strategy (Mar 2025) and Education Estates Strategy (Feb 2026). Verified 22 June 2026.
The /sources page lists the 24 primary URLs that back every numeric claim made across the site. Each citation [S1] to [S24] in body text resolves to a row in this register.
The /sources page lists the 24 primary URLs that back every numeric claim made across the site. Each citation [S1] to [S24] in body text resolves to a row in this register.
All sources carry a last-verified date. The register is reviewed quarterly; specific sources (Ofgem cap, PSDS bid window) are checked at higher frequency.
Legislation (Climate Change Act 2022, DPDI Act) is append-only. Tariff caps (Ofgem) are versioned per quarter. PSDS phase guidance is versioned per cycle.
A procurement officer auditing the worksheet inputs can follow the [S] number from any page to this register, then to the primary URL. The methodology page maps every assumption (A1 to A24) to one or more sources.