The light flow upstairs seems perfect for an upside-down layout. Maybe add one extra skylight above the kitchen area for more balance through the day.

For ground floor bedroom 4 door currently it was open to the left it Will be better if it open to the right so you can clearly see the whole room when opening door

For the shower on left side if you can flip the placement of toilet and sink vertically and Made the door open to right instead left just like the door from reception room it Will be more comfortable since it has repetitives pattern with my suggested fix of bedroom 4 door

For garden room, I Will arrange the cabinet on the right wall side thus I can place sofa near the window on the left near side door and place tv on the back wall then dining table placed in front of back window, this layout allowing people to view both the side garden and the back garden from sofa and people who sit on dining table can enjoy back garden view

For second floor bedroom 1 by fengshui and psychology its not ideal to place the bed along the enterance door pathway, it Will make you sleep less comfortable and flinch everytime someone enter or knock, maybe flip it with wardrobe and make the ensuite door camouflage like accent wall or if you don't want to change the layout probably use curtain or sliding accent wall to psycally hide the door visual for better sleeping

Even if no one entering your subsconsiousnes Will feel something Will come since it was an alley

I really don’’t like the plan.
For me the principal living space is too small, if the purpose of being upside down is views then you need bigger windows. The balcony is way too small for furniture and does not access the garden. The granny annex seems like a personal choice but could cause mortgage problems. If you are basically living upstairs the utility room needs to be on that level. The master bedroom doesn’t have enough storage and triangular window is ill advised for a bedroom.

Personally I think you should go back to the drawing board and start again completely. Next time consider having an attached garage so that the upstairs principal living space can be larger.

An upside down house usually means the view upstair are better than ground floor

The triangular shape isnt window and probably Tudor style

There are less bigger window because the architects might consider how the sunrays Will works all day, could probe people eyes by certain direction when they sitting on sofa etc

More window not always good even if you have AC in the summer it can feels like greenhouse, I know this because I experience it firsthand how you could feel the sun heat through those window

Its recommended to place the utility near bedroom area as it make it easier to pick up laundry from all family member, closer when they had to shower and in the ground floor if you come home with mud covered clothes

maybe they don't have budget for bigger balcony or didnt want the ground floor to lose more natural light exposure if they did as bigger balcony mean they Will covering more area downstair

Theres no Direct stair to garden probably for aesthetic choice and needs of the owner Its actually pretty common if they don't need additional stairs, architect only Made it if the client request it and it pretty rare happen