'Austrian' would make no sense in this context. The Austrians were allies of the British during the Napoleonic Wars and they were assisting the Royal Navy against the French in the Adriatic over this period.
What this entry refers to is the destruction of the Danish fleet, following the Battle of Copenhagen in August and September 1807. The Danes were actually neutral at the time but the British feared that they succumb to French pressure to ally with Napoleon against Britain and Russia. This would have allowed Napoleon to blockade the entrance to the Baltic which would hamper Russia's ability to supply its troops on the continent. When the Danes refused enter into an alliance with the British, the Royal Navy was ordered to capture the Danish fleet so that it could not fall into the hands of the French. After a successful British bombardment of Copenhagen the Danish Crown Prince ordered his naval commander to destroy the Danish fleet. When this order was not complied with, the Royal Navy captured the ships and set about destroying most of them, although several were retained for Royal Navy service. More on the background
here.
While I am certain this is what is being referred to, I have no idea what the actual word is, it clearly isn't 'Danish'.