Would Vickers build a triple turret as a sales prototype?

Could Vickers have built a working triple turret while trying to sell the design to the Admiralty?

It is plausible because a working prototype could test and demonstrate a sales design, but archival confirmation is still needed.

The question recalls Norman Friedman's discussion of Vickers trying to sell the Admiralty a triple turret. An active sales campaign would at minimum require plans and engineering work. In this period, moving from drawings to a working example could be the practical way to test the design and persuade a buyer. That logic makes a prototype plausible and directs further archival research, while the photographed mounting remains unidentified.