This Glasgow Zoo site mentions the Peak District wallabies - and also has this rather charming note about Scottish wallabies:

In Scotland, Lady Arran maintains a very large colony on one of the larger islands; Inchcailloch, on Loch Lomond, from where, in severe winters, some hop across the frozen loch surface to live in the woodlands at the lochside. From time-to-time these are seen (or narrowly missed) by car-borne tourists, causing great consternation.

I love the image of a mob of wallabies hopping across the frozen loch in time to a rendering of "Loch Lomond". They could use it as an advert for Australian Lager.