Patio with 170mm varying DPC level with shallow foundation

[ElmBuilds]

Hi all. Bit of a unusual situation it seems when planning a patio, maybe someone can help:
 

Bought a 1970s house 2 years ago that had an extension in 1975 and later a large interior redesign which included moving the rear doorway in the rear single story cavity wall. No damp problems in the house.

Picture 1: The area highlighted in green are the DPC levels. Left was the extension, middle was where old door was moved from, right is original. Total width of rear wall is ~5125mm.

Picture 2: An isometric view of the recent patio design so far + polycarbonate canopy idea (Unfinished design, but refining it).

 

We had to rebuild a soakaway because the previous failed (No membrane around a stone filled pit near house. It's now 1.2m³ about 5m from house), so we also opted to excavate for a patio while removing several tones of buried construction/refurb waste left behind. 
 

The DPC levels vary wildly across the back, but to make matters worse it's only 35mm higher than the concrete side path on the right side AND it's the absolute minimum height above of only 3 brick courses above the foundation on the right third (allowing 225mm cavity clearance for building regs).

Furthermore the garden slopes upwards from the house (were adding a french drain at between the patio/garden in case), so higher patio would be prefered. Patio will slope away from house.

The foundation extends about 150mm away from the wall. This all makes it tricky to get any kind of drainage channel or slope in there. We believe the foundations are so wide/deep because clay soil around here.

This means a patio almost can't be 150mm below the DPC all the way as it would be cemented to the foundation creating a non-draining area, while also being below all surrounding area.
 

We are very strongly considering a lean-to canopy over almost all the rear wall to remove most of the water getting on the area near the wall (piped directly to soakaway).
We would leave a ~100mm air/stone-filled gap to the wall and either pipework, membrane wrapped stone (then topped), or proprietary solution to ensure the small amount of water can drain to the ground under the patio subbase.

 

Among the options we were considering (left side to right):
A) 150mm Below door DPC on left, slight slope to level with DPC/concrete on the right corner.
B) 150mm Below door DPC on left, step in middle to 75mm below DPC on the right, small step up to side path.
C) ~85mm Below door DPC on left, step in middle to level with DPC/concrete on the right
D) ~85mm Below door DPC on left, NO step in middle, ~75mm ABOVE DPC on the right. ~100mm step down to side path.

 

None are ideal, but our prefered solution is D with Canopy + 100mm air gap + solid provisions to ensure the gap (between house/patio) drains to soil below patio (i.e. so it doesn't just become a solid water collecting channel on foundation).

I don't believe enough water would collect there to warrant a full drain system piped to soakaway nor could it cause any damp issues given even more draining than existing was, despite being above dpc 100mm away.
 

How would you deal with the combined DPC and foundation issue for this patio? or thoughts?