Surely a better plan would have been to build them new enclosures elsewhere at London, before demolishing their old ones?!
Of course, but the reality seems to be that these days they just shuffle animals around into whatever enclosures become available. Exceptions being of course the major builds like the new Lion one. But for other( read 'unimportant' in this case given they have other Monkeys on show) species I think those days are long gone.