Thanks for the suggestions guys.
I've Googled
goosegrass and certainly can see the close resemblance. The arrangement of slightly hooked spines would absolutely fit the "seed dispersal" theory.
What initially surprised me (until I gave it some thought) was the fact that I found it on 1st January - but then I realised that plant seed have to somehow make it through the winter to whatever point in the year it germinates and grows.
Bruce
