I haven't been to Slimbridge for many years now- but this looks like a pretty ugly sort of construction- despite the obvious attempts to make it ecologically friendly it seems rather prison-like. In the flat landscape of Slimbridge surely it looks pretty intrusive?
Hmm... I wouldn't have said so. You only really notice it if you're in the immediate area of it as the hides and obervatories all face away from it and trees hide it from a lot of the captive waterfowl pens. I think it's quite a striking building, actually, resembling (I suspect intentionally) an over-sized hide with all the wooden cladding and lengthwise windows.