Kev - I did your course in Birmingham but not done much real stone since then (spring)
This has come up - she wants it cleaning and sealing - its not very old but is very grubby - it was sealed with a Lithofin product that she does not know the name of and they have been using Lithofin Easy-Care on it - the floor is dull and grubby but I also saw residual grout haze in one area (not pictured) - she says it was all sealed when laid - can you just run through your routine to clean (and re-seal?)
Going back Monday to do it... Any advice welcome
david