Spotted this in FindMyPast's military records
Royal Hospital Chelsea Pensioner Admission Books
Regiment - 3rd Batt. Arty; Gunner/Drivers - William Kirkwood; Date of Admission - 10 Oct 1825; Age - 38 1/2; Service - Private, 19y 273 d (written underneath "Waterloo"); Total service - 21y 273d; Rate 1/0; Cause of Discharge - worn out; Where born - West Ruthen, Berwick; Description - height 5'7", fair hair, grey eyes, fair comp; Trade - tailor.
Possibly "your" William?