After spray

Without

Limescale remover is acidic. Anything acidic will etch the marble. That is permanent.

Trying to have a vertical tiled marble wall refinished is a lot harder than having a marble floor refinished. You can't use the heavy sander/buffer machines on a wall.

Call a company that does marble restoration.

Also look into getting a whole house water softener.

Call a pro, please. It isn't all that difficult, but takes practice and you don't want to practice here.

Thanks for the optimistic answer, according to Clyde its permanent.

Luckily its not the whole wall, only 1 - 2 tiles aka 1/8th of the

Are there any buffing products i could use to make it slightly better?

Permanent as in no home cleaning product is going to remove it.

" Are there any buffing products i could use to make it slightly better? "

No.