Hello,
a quick update. I've had a look at the census return for a Corporal immediately 'above' Robert Berry in the census, and a Sergeant immediately 'below' Robert in the census. According to the Chelsea pensioner records on findmypast, the Corporal was in the Grenadier Guards, and the Sergeant was in the Coldstream Guards!
The list of names is
Corporal (Giles Lewis), Grenadier Guards
Wife
Visitor
Robert Berry Soldier (occupation, Servant)
Sergeant (Stephen Darling), Coldstream Guards
Sergeant, Coldstream Guards
Sergeant
Corporal etc, Coldstream Guards
Private etc
Which may indicate that he belonged to the Corporal or above, in the Grenadier Guards?