Plain linen is the hardest fabric to upholster well, precisely because there is no pattern to hide behind.
On a patterned cloth, a seam that wanders by a millimetre disappears into the design. On plain linen it is a visible line running across an otherwise empty field, and the eye follows it the length of the sofa. The same applies to the weave itself - linen has a clear warp and weft, and if a panel is cut even slightly off-square the grain of the cloth runs at an angle to the frame and the whole panel looks skewed.
So our upholsterers cut plain cloth to the thread rather than to a chalk line: the fabric is pulled to find the true line of the weave and cut along it, so the warp runs vertically and the weft horizontally on every panel of the finished piece.
Seams are then placed where the frame gives them a reason to be - at a change of plane, along the edge of the apron, at the junction of arm and back - rather than wherever the width of the roll happens to run out. On a plain cloth, a seam that has a reason looks intentional and one that does not looks like an accident.