Yes, a description of the call would be nice. I understand that the call and the presence or absence of webbing between the toes are the key features for distinguishing between Ringed and Semi-palmated Plovers.
I'm not sure that many vagrant birds are active vocalisers when they find themselves on their lonesomes in a strange land. Most of the vagrants I have seen in Aus - Laughing Gull, Grey-headed Lapwing, Lesser Yellowlegs, Buff-breasted Sandpiper etc were mute when I observed them.
I understand that one of the observers of this bird is familiar with Ringed Plovers. I asked a correspondent at the BBO whether the bird had been calling. The response I received was that the bird is yet to make a vocalisation that is diagnostic of any of the species considered so far.
Regards, LK