@maggiemae Thank you Maggiemae, they do look peculiar and they have a really interesting courtship display. This involves lots of head shaking and standing on the water breast to breast. I have put a link on to a video showing some of this. If the link doesn't work, try searching on You Tube for Great Crested Grebe Courtship Display.
https://www.youtube.com/watch?v=ORqblRpH9Eg
https://www.youtube.com/watch?v=-O8_DMfPJus