[PaulDavisThe1st]

Two small things there - not trying to take away from your main point.

(1) This is what Americans would call a "row house", and IIRC in the UK is called "terraced housing", which has the huge benefits for all but the ends of the rows that your side walls (the longest walls of the house) are insulated by ... your neighbor's house. So, although the architectural features you mention are indeed drawbacks, their impact is significantly reduced by being in a row of connected houses. It's the single-family/full-detached houses that suffer from these problems more fully.

(2) I don't see the L-shape at all.

[pm215]

For this specific case it's a bit less clear because the house has been extended significantly and so the ground floor floor plan is no longer L-shaped, but if you check the floor plan for the first floor (UK terminology) you can see that the rear-facing square-shaped bedroom has a window facing into the garden, making the overall floor plan an L. The shared walls with the neighbours match up about with the second floor floor plan's extreme left and right edges.

The original design on these Victorian terraces is typically an L shape, where the upright of the L had the kitchen in it, and the base of the L is the main block of the house. This allows the room at the back of the main block to have a window facing back into the garden for light. Many have subsequently been extended for extra space and to add bathrooms, which were not originally present. Partially or completely filling in the corner of the L is popular.

[PaulDavisThe1st]

OK, I see what you mean now. It's a very subtle L :)

I am extremely familiar with this shape - my sister lives in one just like this in Walthamstow (prolly not worth 2M yet though).

[michaelt]

It's subtle - but it's an extra 7m of exposed wall on a house that would otherwise only have 10m of exposed wall (the plots being about 5m wide)

[andrewaylett]

The L comes at the back of the property -- most visible on the first floor of the floor plan linked. Someone's roofed over the side passage on the ground floor to make a bigger kitchen and knocked the two main rooms together to make a larger living room.

That design of terrace is exceptionally common in the UK, where each pair of houses is mirrored, with a kitchen out the back and a side passage letting light into the middle room on each level.