Boomslang?They are going in the old Black Mamba exhibit which is in front of you as you enter the Reptile House. They have had them a couple of years but only now going on show.
Both their Black Mamba's had to be pts due to health issues at the backend of last year. They no longer have any mamba's in the collection. They did mention another type of venomous snake beginning with B which is likely to go on show soon, but can't remember for the life of me what it was.