The register
The register lists Diesel services ltd in Uxbridge as a licensed sponsor on Skilled Worker, an entry that goes back to at least 2026. Rating on the current register: Worker (A rating).
Companies House lists it as Diesel Services Limited, number 03206342, incorporated 1996: 30 years of filings behind the name. Registered office: Lynwood House, 373-375 Station Road, Harrow, Middlesex, HA1 2AW, HA1 2AW. By its SIC codes the business is in professional and technical services.
Holding a licence is the expensive, slow part done. For Diesel services ltd the question each time is only whether the role and the pay fit the current rules, and that is checked per vacancy.