In other words, your usual
"we've got this" spiel

the fact that Melbourne
specifically chose to establish insurance populations outside Australia, and an international studbook managed by Bristol, suggests this is rather more than Bristol "making it look like they are taking conservation action when there is none" and "nowhere else outside Melbourne and NSW contributing to the conservation of the species".
Have just rooted out the most up-to-date information with regards to conservation studbook involvement at Bristol pertaining to island species:
Studbook holder:
Fregate Island beetle (Polposipus herculeanus)
Lord Howe Island stick insect (Dryococelus australis)
Desertas wolf spider (Hognas ingens)
Luzon bleeding heart pigeon (Gallicolumba luzonica)
Mindanao bleeding heart pigeon (Gallicolumba criniger)
Black-naped fruit dove (Ptilinopus melanospilus)
Visayan tarictic hornbill (Penelopides panini panini)
Other Tarictic hornbill (Penelopides spp)
Heavy involvement in studbook:
Partula snail (Partula sspp.)
Mountain chicken frog (Leptodactylus fallax)
Utila spiny-tailed iguana (Ctenosaura bakeri)
Sclater's lemur (Eulemur flavifrons)
...plus lesser involvement in several other studbooks.