I really would hope that Whipsnade would invest in a new common hippo habitat (the current one is so hopelessly "dazed" and "dated" and stick with pygmy hippo only at London Zoo Regent's Park.
I really am at odds why not that ZSL not rebrand both institutions as partners and add-on value with single attractions for zoo visitors at each site (and lo-an-behold ZSL recreated the pygmy hippo habitat quite recently at Regent's Park and now sits content to have just a lone female pygmy hippo there). Just don't make sense .. to me!
Much better in my humble opinion.... (unlikely to happen it seems), but it would certainly create a continuous landscape with other African hoofstock and well something of a great landmark and reason to yahoo, yahoo, yahoo ... visit Whipsnade. Certainly an added visitor benefit.