The register
The register lists Martin & Heller in London, Select State as a licensed sponsor on Skilled Worker, an entry that goes back to at least 2026. The register records its rating as Worker (A rating).
Martin + Heller Services Ltd is the registered name (Companies House number 05396970), a private limited company on the register since 2005. The registered office is at 5 North End Road, London, NW11 7RJ, NW11 7RJ. By its SIC codes the business is in professional and technical services.
Holding a licence is the expensive, slow part done. For Martin & Heller the question each time is only whether the role and the pay fit the current rules, and that is checked per vacancy.