Sink Issues. (2 Viewers)

[Outdog]

Hi All .....
I’m having some sink issues. Firstly, the yellow staining. Is there any suggestions on how to remove it please?

Also now discovered that the waste pipe feed to the sink hole has broken. Any repair suggestions please ?
I’m really hoping that I don’t have to remove the shower unit to access that waste pipe for the sink.

Thanks All

 

[Stonemags76]

Bicarbonate of Soda? Try a small patch first?

 

[Odd job]

What is at the back of it? On the one I had there was a small hatch.