The planner is not an architect…
That would not be essential, a civil engineer would do here as well. But apparently the "planner" is only a "work planning appointee," i.e., a draftsman. That of course won’t work.
What is your planner actually doing? He should be able to solve the problem.
As stated in post #16/17, I don’t see any "problem" at all – unless one is made:
The whole thing please, if possible, with a ceiling height of 2,490mm
... for which I see no requirement here.