When I was at school, in the 60s, I did a project on the Coypu. I managed to get a couple of specimens, sent from the Norfolk Broads, that I used for dissection and building a skeleton
As far as I can recall the name Nutria came from the Southern states of the USA, and it was the name used for the fur, which was why it was farmed in UK pre WWII. The fur was of a quality to match mink, but a lot cheaper.