London at one point exhibited all three species together, according to an old book I got as an early Christmas present called The Zoo Man.
I guess that was a very long time ago now. I have actually seen all three species in the past at both the ZSL sites, but not at the same time.
London Zoo definitely had all three species of zebra on the Cotton Terraces in the 1960s: I recall seeing them there. In addition to the zebras, the Cotton Terraces also housed Przewalski's horse and onager so there were five equid species on display simultaneously (and, of course, many other ungulates too). Who was the author of the "Zoo Man" book you refer to? Was it David Seth-Smith who used to be known as the Zoo Man?
A sight we shall never see again at ZSL undoubtedly. The Mountain Zebra pair were probably moved to Whipsnade where they bred but the stallion later died. The mother and male offspring later moved back to the Cotton Terraces I believe. The Grevy zebra pair at ZSL around this period (late Sixties) were also a mother and son pair.
I criticsised Marwell on Tripadvisor (generally good review overall) for not providing Pygmy Hippos with swimming facilities in their paddock and they said that they were planning to provide them with new accommodation as part of the development plan. Thinking about it I don't remember Whipsnade providing any pools in their paddocks either, just pig arks to shelter in. Is it that they need heated water, that they don't want to swim during the day and just want to forage or is it something else?
The Whipsnade pygmy hippos do have an outside pool in their paddock (although pygmy hippos are not as aquatic as their larger relatives).
I know they have an outside pool at Marwell, but it is extremely small. But then, as you point out, perhaps they don't mind. I can not remember the pools at Whipsnade so they must also be small. It will be interesting to see how they are rehoused.
I love watching Hippos underwater and it would be great if their new enclosure featured a rainforest motif with large viewing windows into a crystal clear river. I don't expect it but I can dream.
Had a look on the photo archive and the pool at Whipsnade does seem a good size. I like to see postings of enclosures as well as head and shoulder shots of beasts as it forms an excellent historic record.
Marwell actually have a similar design to what the hippos at London lived in for a very long time (late 00s-2014ish); no pool outdoors but most of the floor space indoors taken up by a pool/pools. Doesn't necessarily mean that it should be that way, but pygmy hippos are a forest dwelling species first and an aquatic species second, contrary to their larger cousins.
I agree Cliff, and have said so before, a shot of the enclosure is more thrilling to me than just another face shot.