Interesting you should bring this up as I found the site of the company that provide the parrots and sea lions only yesterday. They also provide them for TV shows and films including the excellent 90s kids TV show Harry's Mad!!
Was the questioner trying to catch PWH operating illegally?
Weird to hear that they rent the animals.... seems like a waste of money to me. Unless it doesn't cost much obviously...
They have always been leased - spose it must work in their favour - could hear the sealions barking away today on my travels around the perimiter of the park... photos and blog bit in the present section somewhere !!!