Our Blanco induction cooktop came with an instruction sheet which states it needs a 4mm gap directly under the bench top for the fan at the front of the induction to blow out the air.
I showed this to the kitchen guys and they said they'd never done that with induction before and not to worry. (So basically, "If you want that done, we're not doing it!")
I'm still concerned though...
Just wondering who else with induction does have that gap?