The wallabies of England

How many wallabies are wandering the wilds of England?  Parrott and colleagues assessed the situation in 2008, issuing a study:

The Status of Scarce Non-Native Birds and Mammals in England,” Dave Parrott, S. Roy & M. Fletcher, Central Science Laboratory, December 2008. The authors report that : “Established colonies of wallabies… are known to have persisted for over 50 years.” A partial list of sightings is reproduced here (click on it for the entire report, including the full list):