Captain Prevost's company of the 5/60th was assigned to Kemmis's brigade but missed the battle according to Butler, King's Royal Rifle Corps, Vol. 2, p. 138.

The Brunswick rifle company was definitely at Albuera according to the memoirs of its commander, Captain Friedrich Ludwig von Wachholtz. The presence of the Brunswickers was also noted by Julius Hartmann, the commander of the British artillery.

Both these points are covered in my own book on the battle, Albuera 1811.