Use the identifier with its country and register
There is no single worldwide company-number format. A foreign identifier should be checked against the registrar responsible for that entity, with attention to prefixes, punctuation and legal form. Request the incorporation jurisdiction when a document provides only digits, and compare the legal name returned by the official service with the name of the contracting party.
Resolve conflicting identifiers before relying on a match
The Companies House overseas directory and European registry guides help locate issuing authorities. GLEIF search can add a global LEI cross-reference for entities that have one, but absence from that system does not prove that a company is unregistered. If records disagree, preserve the competing identifiers and obtain a current extract instead of silently merging the entries.