The ODNB article makes no mention of William being injured and losing a leg in June 1794, from the article - he followed Captain Cuthbert Collingwood to the Barfleur in 1793 and took part in the action on 1 June 1794, then from July 1794 to October 1795 he was with the Theseus.
According to the article he was born c1751/2 in Stonehouse Devon; he didn't marry; and when he died he left his five sisters £2000 each. His Will is available on the National Archives website "William Prowse, Rear Admiral in his Majesty's Navy, of St Pancras, Middlesex; Probate 22 April 1826; PROB 11/1711/365"