Could a Vickers 14-inch turret take Royal Navy 13.5-inch guns?

Would using a Vickers triple turret force the Royal Navy to adopt the company's 14-inch gun?

Not necessarily. The larger mounting could accept Royal Navy 13.5-inch guns and might even provide extra elevation margin.

The question notes the Royal Navy's reluctance to surrender control over gun development by adopting a Vickers 14-inch weapon. The answer separates the gun from the mounting and argues that a turret sized for 14-inch pieces should also accommodate the slightly smaller 13.5-inch Royal Navy gun. Lower weight and diameter might leave useful margin for movement or elevation inside the mounting. Vickers' willingness to sell designs made a Royal Navy adaptation commercially plausible, though the exact engineering still requires evidence.