i've had a foundation inspector look at my floor:
as you can see there is quite a deviance on the right hand side.
he says that any future movement is likely to be limited; although, cosmetic distress is likely to develop over time. the foundation is of continuous perimeter, reinforced concrete, spread footing type. past (not by me) re-leveling had compromised some of the anchor bolts, but were fixed with some strong ties.
my question is how could the floor be re-leveled and how much is it likely to cost?