It'd be brill if kitchens all came standard sizes and walls could be guaranteed to be parallel.Yup think you pay a bit extra but well worth it me finks. Plug n play kitchen
When I did our kitchen I had to lose 1 or 2 mm off each of three units to get them to fit along the wall under the window, together with the built in dishwasher. The doors were of the sort you couldn't trim down, so I had to work with the allowance allowed on the units. So of course I could only use the pukka fittings one on side each time. And I had to modify the backs of quite a lot as I was extending the ring main etc. We also went for a lot of drawers as both W and I have back problems. I bet those don't come already made up!
Despite all that, what with the "magic" corner unit where you pull open a door and it swings open and out while another slides into view and other stuff, I quite enjoyed it. And it sure is easier to work with.
Have fun fitting it!