How interwar aircraft prototype competitions worked

Did the Air Ministry see company designs before prototypes were built?

Yes; officials selected paper designs for prototypes, which were then tested by the company and government before production decisions.

The ministry first reviewed paper proposals and selected designs worth turning into prototypes. Company test pilots refined the resulting aircraft before government establishments tested them hard enough to expose structural and operational weaknesses. Officials could then request changes before choosing a production design. Companies were also free to risk their own money on unsolicited proposals, which created room for initiative but could leave a manufacturer carrying the full loss. The exchange contrasts that competitive sequence with modern programmes in which the government more often defines a detailed specification before industry commits to a design.