Agree. Quite likely WMSP wanted to exhibit the species with whatever animals were available and were supplied with animals needing to move(I remember one of them- the 2 year old male?- was from Whipsnade) irrespective of their future potential as a breeding pair together. Rather irrelevant now as its been rectified anyway and longterm has not affected breeding potential-but worth noting.
I see no reason why they could not have Black Rhino too- but another 'car-less' exhibit would be necessary.
C'mon... I'm trying to draw this tangent to a close.
Why would a car-less exhibit be necessary? Ree Park, Ebeltoft, seem to manage it with no problem...