Steel seat base for C15

[Barnsey]

Hi All,

  I bought a new cover for my seat, but on stripping the old cover off the base is really rusty. Just about salvageable but getting thin at the edges.

  I don't really want to buy a complete seat at close to £200, especially when I have a new cover.  Does anyone know where I can get a replacement base? 

  BR,  Ian