The register
The register lists Harmer Slater Limited in Sutton, Surrey as a licensed sponsor on Skilled Worker, an entry that goes back to at least 2026. Rating on the current register: Worker (A rating).
Harmer Slater Limited is the registered name (Companies House number 07167165), a private limited company on the register since 2010. Registered office: Unit 8 The Aquarium Building, King Street, Reading, Berkshire, RG1 2AN, RG1 2AN. By its SIC codes the business is in professional and technical services.
A licence says an organisation may sponsor; it does not say it is hiring today. The way to find out is the same as for any employer: the careers page, the job boards, and a direct approach with a UK-style CV that says early that sponsorship would be needed.