Help with Identification

Looking through some of the other pictures I took at Cresswell the other day I came across these two. After finding out that there were Curlew Sandpiper there I am now starting to wonder if there are two here in amongst the Dunlin one in the centre and one on the right. I have looked through a couple of books and they do look promising for Curlew Sand but any help would be appreciated, as they would be a lifer for me.