That is another great idea and so I have asked Tim to check his resources - he has more stuff on silhouette artists than you can shake a stick at!I have found the auction for this piece online. It is the profile portrait of an officer. Water colour on paper. The artist is J Nock of Plymouth and it was painted in 1803. At least that’s how I read the description.
Meanwhile, I have also sent the discoveries over to him.
Thank you all for your help with this.