After finally identifying some "grassy" leaves beside the woods as a type of Woodrush (based on cilia on leaf edges), it turns out to be an interesting ID challenge. potentially. Or it could be easy. Here's how hard it could be:
In the Vegetative Key Woodrushes come out to JN, but I'll need to take a closer look to see if it can ebe ID'd wihtout flowers. Or even with!
With leaves clearly >6mm there are few choices, so I'm punting for Luzula sylvatica at the moment.
(Luzulu sylvatica it was - not much choices for a Wood-rush 12mm wide. Mercifully doesn't seem to have been one of the tricky ones)