I agree it may look smaller in the photo. Width-wise it basically covers the old shop up to the toilet block, so quite wide! Not sure about depth-wise, but definitely coming on quickly!
The new entrance complex houses a shop (about half the size of that at London Zoo), cafe, ticket office, toilets and meeting rooms. The complex is L shaped with the view shown being about two thirds of the long arm of the L taken from within the zoo. See my post of yesterday for view from the other side.