Grinder marks on porc - TilersForums.com

[Cranbrook]

Here's the scratches...

 

[Concrete guy]

Go to Halfords and look in the paint detailing section for a product called Farecla G3.

It's kind of like T cut, will need a bit of elbow grease, but it "cuts" in a very slow and controlled manner. You'll know pretty quickly if you're going to get a result. Ideally use it with a sponge applicator.

This kind of thing:-

That's the most likely solution to your problem.

For those interested, this product will remove light scratching from the surface of man made quartz (but only light marks) but you'll need a mechanical polisher with a felt mop or lambs wool bonnet to get any sensible degree of finish. sub 2000 rpm target speed preferable sub 1000 rpm.