Unfortunately it was a while ago now and I don't have any more photos, however it sort of reminded me (its not the exact same) of this plant I found near Sutton - Chondrilla juncea (Skeleton Weed) which Michael has identified. If I see any more around I'll get some better photos.
Thanks @mcosgrove - I was actually thinking about that before and there was some Skeleton weed in that same area later on, and it seems the most likely thing in my opinion as well.