Do you have to have wall units on that wall? you could go for shelves and avoid the headache. Or maybe you could get a carpenter to box the gap:or build small fake units: Or use some slim cabinets:

Tall units up to the ceiling can look very nice, although would function as displays mostly. Honestly standard height kitchen wall units wouldn't concern me, they might accentuate the height which is not a bad thing at all. Alternatively if you have enough storage in the base units why not skip wall units altogether? Open shelves or even nothing, just a stunning splashback

we live in the semi detached house and just noticed that the ceiling height of our neighbors loft is at least 15cm higher than ours. Also, our ceiling height seems to be lower than the original architect's plan. any idea what went wrong and would it be possible to fix it? our current ceiling height is a bit short of 2m and 15, even 10cm more would make a big difference.

Good for you. what's your dilemma?