Is 16-18 still collectively known as Knox House? 

It looks like Knox Capital Solutions may have moved to St George's Street, but some officers of the company still have this listed as their correspondence address.

https://find-and-update.company-information.service.gov.uk/company/10433360/officers

https://knoxcapitalsolutions.com/contact-us/

https://services.gov.im/planningapplication/services/planning/planningapplicationdetails.iom?ApplicationReferenceNumber=23/00829/CON