Wader ID

Hi, any help with the ID of the bird on the left alongside Dunlin please? 

It was among ruff, godwits and the lone dunlin. This bird didn't move from the spot for the 15 minutes or so we were in the hide.

For me I think it's another ruff, but the shape and the fact in didn't move at all leaves some doubt.

Freshwater-ish pool in Norfolk not far from the coast.

Thanks in advance,