When a contemporary extension is well-designed, it shows. It shouts, actually. I learned from the owner of this house that her sister, an architect, had designed the space. One notices immediately the two square, rather than three rectangular skylights, in symmetry with the sliding glass doors. And also the fact that each living zone is distinct yet they subtly flow into one another. So even on a cloudy winter day in New Malden, this interior — created by Cube of Teddington — shone.