Combate de San Pedro (7.6.1807), a 20km de Colonia:
"7 Jun 1807 - Pack steals out of Colonia (Uruguay) with 541 men of the 40th, 225 men of the 95th, 278 skirmishers, 61 troopers of the 9th Dragoons, 34 gunners and 2 field pieces to surprise the Spanish at San Pedro [Argentina] ...."
http://books.google.com/books?id=_9-gAAAAMAAJ&pg=PA16 (see footnote).
"... The 95th subsequently saw action in June at San Pedro where they, the 40th and light companies, fought against the Spanish force that had crossed from Buenos Aires and defeated them ...."
Historical records of the 40th (2nd Somersetshire) regiment p. 105ff: