1930s steel rectangular vintage Dunhill Waterproof watch

A rare stainless steel rectangular vintage Dunhill Waterproof watch. The case measures 22 x 38mm (including lugs) with 16mm lug size. The case is signed Tavannes Watch Co., Acier Staybrite and numbered. The case back is secured with four screws to the corners with a particular crown fitting. The manual wind movement, Ref. 364, is signed Tavannes Watch Co., with 17 jewels, unadjusted, patented and numbered. The black dial has white alternate Arabic numerals, an inner minute track, with a subsidiary seconds dial and fine steel ‘re-lumed’ hands. The dial is Dunhill above the centre, with waterproof below.