The issue is that we’re talking about two different subspecies with (marginally) different environments and (completely) different appearances. The northern subspecies is smaller and is less furry, as the climate it’s found in is far more arid and tropical as it’s closer to the equator. The southern subspecies, despite also living in a largely warmer climate than the UK, has to deal with lower temperatures given that its found in areas further away from the equator, and thus has evolved to be bigger with a thicker coat.
If southern koalas were more prevalent in Europe then I’m sure there would be more open topped enclosures and we would see koalas in more outdoor situations, but the fact is that Longleat is the only true European (I’m not counting that Israeli zoo ZTL lists) zoo with southern koala, and therefore the only zoo where koalas are more likely to be seen outdoors in chillier weather and can withstand wind tunnel style environments...
People may try and argue that surely that makes Longleat a better enclosure as it’s more suited to the UK, but that’s not the game here. The game is which enclosure best suits its inhabitants, and both do so in a multitude of ways. But, as has been the case previously when matches are close/hard to compare, the second resort is husbandry and breeding record. And the truth is that Edinburgh’s stand-out husbandry and large amount of breeding says it all.
(Don’t get me wrong, I really like Longleat’s, but prefer Edinburgh’s!)