The 4 June 1810 "Return of the Royal Horse Artillery, Royal British and German Artillery and Drivers in the Field under the Command of Brig. General E. Howorth" (See The Dickson Manuscripts Volume 2, page 218) lists Captain Lawson's Brigade 9 pounders and 2 light six pounders from Captain Hew Ross' RHA Troop under the command of Lieutenant W. Elgee. They are listed as being in reserve at St. Jago.
I can not find St. Jago, San Jago, nor Saō Jago on a map. Does anyone know what it is called today?