How a private company's battle fleet would concern the Royal Navy

How would the Royal Navy assess the Imperial Iron Brewing Company with two ports and four or five first-rate warships?

As a significant potential threat, although British officers in the company could encourage cooperation and an East India Company-style relationship.

The question's fictional Imperial Iron Brewing Company controls two ports, substantial infrastructure, and four or five first-rate warships. That fleet is large enough to be treated as a significant threat. British naval officers within the company could also encourage the Royal Navy to regard it as doing useful work on Britain's behalf. The comparison is with an East India Company operating in the Caribbean, combining a commercial organisation with substantial maritime power.