Leaf appears channelled, like a stick of celery towards base. Large nuts! 4-5 by 2.5-3mm. Juncus tenuis?

EDIT 05/04/2018

'Leaves reduced, long culm, no obvious leafy involucral bracts' - Cam Kilgour

'A %^&$ to get out of the ground, nearly gave maself another hernia' - Andrew Marshall