Sorry, but that's having vultures for the sake of it.
That aviary was built for waders - it's not big enough or tall enough for Gyps species, and it would be barely adequate for Egyptian Vulture. For the money spent on this exercise, this should have been better.
Does ZSL work with any Indian vulture breeding programs?
Maybe they're thinking long-term, about bringing in Indian species to breed them....?
...or am I just wishfully thinking again...??