Plot selection & house orientation

To add to : Development plan, part C point 2.3: Semi-detached houses in WA2 must be congruent. This means that coordination with the neighbors is more important than ever. This alone can be a reason to exclude a particular property...

But "only" with regard to building line, roof shape, and roof pitch.

I'll answer in a batch, since my post with umpteen quotes would probably fill almost an entire page on its own ;-)

If someone finds it pleasant to be separated from the neighbor in their own access/driveway situation, I will of course point out that an underground garage entrance/exit weighs significantly more heavily. Unfortunately, the development plan says nothing about where the underground garage should have its entrance/exit.

To readers wishing for an asymmetrically oriented semi-detached house, I gladly point out that thanks to we have an example of a fraternal semi-detached house on board here. However, I rather recommend the original poster to refrain from this building plot offer, since the description of his house wishes in my assessment is practically incompatible with the possibilities set here or at least will exceed the compromise pain threshold.

Among other things, the development plan states that the house should either become two-storey only through its attic or in the sense of an alternative villa be two-storey with only a rather modest attic (DN II=I+D from 34°, DN II=II up to 33°).

The required "congruence" between the halves does not demand twin-like similarity, but overall I expect a, to put it kindly, "considerable dissonance" between pretty much everything that the average semi-detached neighbor might envision and the original poster's ideas. Moving the halves away from 90° deviating cardinal directions helps little in overlooking this. However, I consider it possible, due to the corner development, that the original poster in half 14 can have a gable-end house and the neighbor in half 15 a eaves-end house with technically the same ridge direction—equality of entry side is not required here. A sort of Solomon's egg of Columbus ;-)

Among other things, the development plan states here that the house should either become two-storey only through its attic or, in the sense of an alternative villa, be two-storey but have only a rather modest attic (DN II=I+D from 34°, DN II=II up to 33°).

..and where does the original poster write that this might not be sufficient for him?

...with technically the same roof ridge direction, I consider it possible that one can have a gable-end house "by feel" and the neighbor in section 15 a house with the eaves facing the street...

What exactly is a "gable-end house by feel"?

..and where does the OP write that this might not be enough for him?

Nowhere, and nobody claimed that either. As a reminder: the two halves are practically required to have the same profile. "II" as "Anstattvilla-II" or "II" as "I + full-story attic" are two very different pairs of shoes that cannot be reconciled. We are dealing with an essential consensus dimension here, which must already be considered a test of strength between semi-detached house partners (or opponents).

However, I also see that as a problem. Even if you consider yourself to be willing to compromise, in the end it is usually the wallet that decides what is possible or not. It already starts with the ceiling heights. It would be easier if the requirements were even stricter and precisely defined. But let's wait and see. Maybe the OP will be lucky. That does happen sometimes. ;)