Hello! Please critique my square floorplan

[Eager beaver]

Hello to all the self-build experts! We're hoping to demolish our existing house and build a new one in its place. Currently waiting on planning permission, which is taking a frustratingly long time....

 

In the meantime, I am of course spending every spare moment obsessing over floorplan tweaks. Our plot is quite narrow and the neighbours quite close so we don't have very much flexibility on overall structure. I'd appreciate any views on what we currently have planned. The rear of the house (open plan area) faces South-East. The black lines are the plot boundary (so we have a bit over a metre on each side). There will be a small basement plant room, access via a staircase under the main stairs. The red outlines are the existing house - probably not very relevant!