The re-enamelling of a cast iron bath is a very specialised process. There are some companies that advertise and offer a home 're-enamelling' service, but this is not genuine vitreous enamel and is in fact a type of paint.
Genuine vitreous enamel is a type of glass, which is fused at high temperatures to achieve its unique combination of hardness and durability, which is unmatched by other finishes.
Re-enamelling will involve shot blasting your bath to remove the existing damaged / worn enamel. It will then be coated with up to three layers of vitreous enamel. Each layer will be fused to the surface by heating in a furnace to a temperature greater than 750 degrees centigrade. It is this genuine vitreous enamelling process that gives the quality and long-life expected of a cast iron bath and returns it to its former elegance.
Not just Baths..
Kingfisher can apply the vitreous enamelling process to any cast iron bathroom equipment, such as cisterns or sinks.