The size of the check meant it was impossible to pattern match correctly but it doesn't show that much when worn.
To change the sleeve shape take the sleeve pattern piece and fold back 14 cm at the underarm.
Then redraw the sides of the sleeve so that they are parallel as shown in red above.
Cut out and make as instructed in the pattern until the neck, cuffs and hem.
For the neckline I used 18 mm elastic and 22 mm bias binding as the casing. For the cuff I used 18 mm elastic and turn the sleeve to form a self-casing.
Finally for the hem I left the selvedge un-hemmed, as I liked the detail.
I washed the finished garment, as I love the rumpled look of the linen with its irregular slubs.