The register
The register lists Portview in Belfast as a licensed sponsor on Skilled Worker, an entry that goes back to at least 2026. Rating on the current register: Worker (A rating).
At Companies House the business is Portview Limited (company number 03754501), a private limited company incorporated in 1999, 27 years ago. The registered office is at 61 Leigh Hunt Drive, Southgate, London, N14 6DF, N14 6DF. Its filed activity puts it in it, software and media.
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.