Development Plan - Interpretation of Eaves Height

Do you think the spot where your arrow is is more than 3.50?

Do you think the spot where your arrow is pointing is more than 3.50?

Yes, that is about at parapet height. That is usually about 90 cm above finished floor, but here it is supposed to be only about 65 cm above raw floor, practically about 40 cm too high if we still count about 15 cm floor construction. Theoretically, the OP could refer to the development plan; according to the wording, he can orient himself on the raw ceiling of the ground floor – but that would clearly contradict the single-storey nature and would assume a street level at cellar floor level. So even a newly appointed judge without an expert would recognize here that what is written cannot be meant. Then, similarly to a severability clause, concluding that what was meant should be applied instead, in my opinion, is more reasonable to assume than that the development plan is "too indefinite" for this reason and quasi considered lawless in this point.

Hi, we have exactly the same eaves and ridge height - see my profile picture

This slip in the wording with the rawceiling is so nice, you can practically fit a 2.5-storey building.

Hi, we have exactly the same eaves and ridge height - see my profile picture

... and it is clearly below the parapet height, as you can see:

This slip in the wording with the rawceiling is so nice, you could basically have a 2.5-story building.

But it says raw ceiling on the ground floor

But it doesn’t have to be, since in this case you simply plan the ground floor slightly larger and box in the upper floor at about 1.30m or so and install a knee wall.

That’s right. That’s how you build, and you always have. In times of the townhouse villa, people just don’t think about the obvious.
On the ground floor, you then have a bit more space for the utility room or the office, which later becomes a bedroom or even an entire parents’ wing, and in the attic there will be enough room for great built-in wardrobes.