The size is helpful shivvy, as that can eliminate quite a few waders, but the light and also tthe distance can play tricks so identification particularly of waders who tend to be mostly brownish at this time of year can be a nightmare.
Taking the Starling at 21cms as your benchmark eliminates two of the suspects ie Curlew, the largest of the waders (a huge 55cms) and the smaller cousin the Whimbrel at 41 cms although the latter is also a plumper version of the former.
The only other wader with a downward curve is the Curlew Sandpiper at 21 cms. This bird is on migration at the moment so is another possibility as it's the nearest in size to the Starling.