First stage in the making of the plastic body is the glass-fibre matting prior to placing it in the mould where it will be impregnated with polyester resins. Several layers are built up in this way to form the body skin.       The body building process involves the construction of a light-alloy prototype shell from which five glass-fibre moulds are made. The five moulds are bolted together to form the complete body mould.   Rear suspension of the single rear wheel is by swinging-arm and Armstrong coil spring/damper unit. Final drive is by roller chain and sprocket from a three-speed reverse Albion gearbox. The Excelsior Talisman Twin engine with blower cooling is clearly visible.       The completed chassis units are lined up for inspection. The robust chassis consists of 14 gauge channel-section steel longerons and tubular cross members.   A really spacious interior and capacious door pockets are outstanding features of the Coronet. The floor-mounted gear-lever can be seen just ahead of the wide bench type seat. A large dial speedometer is conveniently positioned, and there is a pull-out handbrake.       The final stage of construction is when the windscreen, sidescreens, hood, instruments, seats, carpet and trimming are fitted. The hood gives good weather protection on those rainy winter evenings allowing for easy removal when the sun is shining.   Even the Coronet trimming is carried out at James Whitson and Company. Here a skilled upholsterer puts the finishing touches to the comfortable seat squab. Hoods, sidescreens, tonneau covers, carpets and so on are all made on the premises