Could someone ID this for me please i am really struggling with it.
The bird in the photo is an adult Knot in winter plumage.
The legs are not black (compare to the colour of the bill), but are the dark grey colour typical of adult Knots in the breeding season (and many individuals during the winter - the legs aren't always yellow). The pale fringes to many of the mantle feathers and wing coverts suggest that the winter plumage is fresh (and the single obvious black 'spot' on the upper rear flank is probably a retained breeding plumage feather).
Some Knot do have rather long bills, the length of bill on this individual would not be exceptional.
Dunlin do not look as heavily built, rarely have markings so far along the flanks (grey markings extend almost to the underrated on this individual) and would not have barred feathers on the upper tail coverts.
Sanderling are always short billed, would tend to be paler above (except as juveniles, when the upper parts have black centres to the feathers), have unmarked flanks, lack the barred upper tail coverts and typically have more white on the face/forehead.