Apparently, the battalion had a headquarters and 12 companies.

1810: One company in the 4th Division, 2 companies in the 5th Division, and the Headquarters and nine companies were in the Light Division.

1811: Initially, one company each assigned to the 4th and 5th Divisions and the remainder to the Light Division. On 1 February, the Headquarters and nine companies were assigned to the 4th Division, but on 6 March they went to the new 7th Division.

1812: One company to the 4th Division, 2 Companies to the 5th Division and the remainder with the 7th Division.

1813: One company each to the 4th and 5th Divisions, headquarters and nine companies to the 7th Division.

1814: One company to the 4th Division, two companies to the 5th Division, and the headquarters and nine companies to the 7th Division. I have no idea where one of the companies usually assigned to the 5th Division went in 1813.

Source: Wellington's Army by Oman, Appendix II, pages 343-373.