It's 3 weeks old.
Its basically where they would have to step out (and down) into their out-house/pantry, so instead of having a step they have now leveled it (raising it up approx 4"), I looked at it the other day (whist the plasterer was mixing up, and a kitchen fitter and sparky working away) and it looked dusty and sandy to me (but this could be because of all the work going on).
I would rather just seal it as its such a small area, BUT if tomorrow when I can get in there properly I see its crumbling away I will have to tell them it needs hacking out and re-laying. (I don't think its that bad though).