Hi Kev.
This is one of my old clients property where he has discovered this marble fireplace which has been painted over with oil based paint.
If I will manage to get rid of all the paint first I will hand polish it using diamond polishing pads to polish off all the scratches and use the honing powder for dull finish and seal it in the end.
As for the time scale it may take a day or even longer depending on progress.
What would be your best plan of action on this one bearing in mind that I cannot just walk off this job.