I'd say Edinburgh or Paington. Well, Any Australian animal really. Edinburgh last time I checked: 

  • UK's Only: Queensland Koala
  • Swamp Wallaby
  • Rainbow Lorikeet

Paington:

  • Grey Kangaroo
  • UK's Only: Kiwi
  • UK's Only: Echidna

London:

  • Emu
  • Red Kangaroo

 Whipsnade:

  • Eastern Grey Kangaroo?

Amazon World Zoo Park (Isle of Wight):

  • Common Wallaby (Normal colour/Albino)

No Platypus/Quokka Outside Australia as far as I am aware. As I said before, also no true dingoes either.

    Thanks as always, The creator