I do not know but I sympathise.
I bought a double bowl stainless steel sink, but did not use it immediately and stored it until I got the kitchen sorted and the new worktop was fitted. When it was all in, not immediately but after a while, I noticed 5 small black spots behind/to the left of the tap. I never knew that was even possible ! I've had to ignore it ever since. I believed that because I'd had it left in its box, in a room, for some time prior, any complaint would have been dismissed so I never embarrassed myself by trying.
Something for folk to be aware of when deciding what type of sink to buy.