Anthony

It appears that Villiers was British Ambassador from 1808 (arriving in December) to February 1810 when he was succeeded by Charles Stuart.

See page 101

http://books.google.com/books?id=eCC8AAAAIAAJ&pg=PA101&dq=john+villiers+lisbon&lr=&cd=37#v=onepage&q=john%20villiers%20lisbon&f=false

See also Fortecue History of the British Army volume vii page 432.

You can find details of Villiers political life in

The House of Commons, 1790-1820, Volume 4
History of Parliament
The House of Commons, 1790-1820, R. G. Thorne, ISBN 0436521016, 9780436521010
Boydell & Brewer, 1986

List of Ministers to Portugal:

Page 35

The Foreign office list and diplomatic and consular year book. Harrison and sons., 1857

http://books.google.com/books?id=Uc9kGajk1NUC&pg=PA33&dq=charles+lord+stuart+de+rothsay&lr=&cd=9#v=onepage&q=&f=false

John Villiers became the Earl of Clarendon.

Charles Stuart became Lord Stuart de Rothsay.

Good hunting.

Ron