I’m onto the leg! There’s a bit of a hole where I rejoined the heel to the instep, so I might need to do something else on sock two.
The pattern on the instep and leg is a cross stitch rib (see below)
Cross Stitch Rib – Multiples of 3 stitches
R1: *Skip 1st stitch, knit into second stitch, knit into skipped stitch and then slip both stitches off the needle, P1, repeat from * to end of round.
R2: *K2, P1, repeat from * to end of round