Whimbrel passage

Looking at the photos by Olivia and Rhodri I would have no hesitation in saying that they are Whimbrel.  This is peak migration time for Whimbrel and they are often seen in the loose flocks seen in the photos. 

While Curlews are not unusual on passage at Aberystwyth they almost always appear in ones and twos, occasionally in very small parties.  

Also, with the aid of a very good magnifying glass, the bills on these birds look more Whimbrel than Curlew.

P.S.
The only new migrants I have seen in the last few days are Sand Martins on the Ystwyth near Llanilar, and it's pleasant to sit outside the house and listen to singing Chiffchaff and Blackcap.