Ofcom is an independent regulator; it's far from the "first-party" you're implying it is.
It has to obey instructions on prioritisation from the secretary of state and has no real operational flexibility.
As with much of the (dire) UK legislation here, the government saying something is true until it is blue in the face does not make it true.
Ofcom has operational independence. Neither its investigations nor its enforcement actions are directly controlled by the Government. The Government does approve Codes of Practice but if it doesn't approve, it can only request modifications. It's still up to Ofcom to decide how to interpret and implement. Secretary of State interventions are, by convention, rare and subject to Parliamentary scrutiny.