If you goto the BWC on an arranged photographic session you will have access to the
Otter enclosures as well as access to most of the other enclosures. I was there last November, all on my own

Snowing hard, lying on a waterproof sheet getting images of the
Otters. When they get use to you and start walking all over you the cold and the snow is forgotten and it certainly made me feel at peace. Bad description, but you get the idea