Having just discovered that I've cocked-up, I'll expose my error in the hope that someone is saved from doing the same thing. I'm just refitting the kitchen and set the carcass tops at the standard height recommended by the supplier of the carcasses (Homebase). Everything was fine until today when I installed the dishwasher (which only just fitted under the worktop); as I was doing this a little light glimmered between the ears - what about the flooring? You'll have guessed by now - once the flooring is down it's not going to be possible to get the dishwasher out! I suppose I could remove the worktops, plumbing and hob so I can get to the screws fixing the carcasses to the walls and then adjust all the carcass legs, but my inclination at the moment is to leave it and deal with it if the dishwasher fails before we move house - it's new so the odds might be in my favour ;-)
On a related note: the Homebase carcasses are pretty poor quality and I wouldn't recommend them; the doors and "luxury drawers" are excellent though.
Dave