Hi tiler
yes you are right - it was a metal mark from slipping with a grout removal tool. So if I confused anyone with the 'scratch' description then sorry about that. It looked like a big scratch to me.
I had tried wire wool on an old tile and the results were disasterous - an even bigger mess.
As promised I tried as many ways of removing my 'scratch' as cheap as possible. Tried bath cleaner, toothpaste and t cut and car polish
The clear winner, beings none of the others appeared to work was by using a product I bought for cleaning the chrome bits on my frogeye. Similar to solvol autosol - I used 'Peek' - it says it cleans, polishes protects all metals, fibreglass and ceramics.
I used my dremel with a small buffer pad soaked in Peek set to a medium speed and after about 10 mins half the job is done. Well impressed.
Hope this info helps
frogeye