The photos show the OEM 190A passenger's seat, and the driver's seat is similar. It should not be difficult to modify a set of 1930 or early 1931 Tudor seats to work.
The hinge rods are made from a set of radiator support rods. The knobs on the hinge rods are windshield lock knobs. As Vern says, you can buy reproduction hinge brackets for the 190A. Reproduction rear feet are also available, or you can make them from carriage bolts.
If you are a member of the Victoria Association, you can purchase a book that has excellent diagrams of the seats for the 190A, and a lot of other info about the 190A that is not available elsewhere. Just contact Vern to join.