On a lake in a quiet park near Sherwood Forest. Spent a lot of time under the foliage / trees at the back of the lake. Lighter in size and stature to mallards around. More of moorhen / coot size and build.There were two of them. One had a more orange bill than the other. Striking markings on head/ face and also a bright white rump. Only had iPhone and no binos so this is the best photo/video we got as it didn’t come close.