Hi, Installing a new kitchen, not 100% by myself but figured I could fit base units not problem. Until I hit a problem.. Found the highest point on the floor and started installing the kitchen along the back wall (U shaped kitchen) only problem is now I have got to the end I have a 18cm gap from floor to bottom of base cabinet, while at the other end it is 16cm (to account for plinth and flooring). I've triple checked the units are level on top so I'm assuming the floor slopes. How do I correct for this? Can I get plinths taller than 15cm and even this out? Maybe thicker flooring underlay? It's a 2cm difference at one end which is pretty significant. Would rather not have to start again!