Jeff, I have a theory about the identity of this 'Admiral Leeming'. My ancestor Henry Rae was a Scot.I'm guessing if he was captured in a naval engagement it was English Channel/North Sea when forays were made on French ports. I think Admiral Leeming was George Elphinstone, 1st Viscout Keith. From 1803 to 1807, he was commander in chief of the North Sea.He oversaw actions to prevent a French invasion including forays against the French. Elphinstone's mother was Lady Clementina Fleming and she was an heiress and of more illustrious descent than her husband.
Lady Clementina, heiress niece of Charles, 7th Earl of Wigtown and daughter of John, 6th Earl of Wigtown, (by his wife Lady Mary Keith, daughter of the 9th Earl Marischal), married Charles, 10th Lord Elphinstone, and subsequently inherited the extensive Fleming estates. She left these to her son’s second son, the Hon. Charles Elphinstone, who added Fleeming to his surname (note the idiosyncratic spelling) and adopted the Fleming of Biggar arms, placing Elphinstone in the second quarter. I have a vague recollection of Keith using the Fleming name in his younger days.
And this is where I believe this strange Leeming/ Fleeming/ Fleming name came from. Viscount Keith was famous as a Scots sailor and famously lost his ship and many crew of Scots origin. I believe Henry Rae, a Scot sailor from the Borders, was part of the larger Scottish maritime fraternity and served under Keith, andcalled him by his noble Scottish family name.Anyway, that's my theory.