It would be a lot of expense. Its taken them fifty years to get around to building a properly designed house for them (even if its not being used properly!) and I presume they can keep three females (plus small calves) in the new House, as it has 3 stalls, though I don't know if it was built with that intention or for two females and the male. (I also don't know if they intend to keep the young female longterm or not) I think the bull still lives in the old quarters because of the arrangement of the paddocks (only two are accessed from the new house)
Knowing Whipsnade as I do, I think the answer to your question is 'NO' (unfortunately).
Nor do I think they will do anything about changing the access of the indoor poolsin the new house(they certainly haven't so far and this House has been open about two years or more now).
On the signboards outside the new house there is a quote from a ZSL scientist, something like 'now in this specially designed house our Asian Rhinos, the most aquatic species of rhinoceros which likes to immerse in water for many hours a day, will for the first time at ZSL have access to heated indoor bathing facilities'
I think maybe they should remove that bit if they don't improve things..
