Steven's link covers the orders issued by Wellington for 1815. Wellington had issued similar orders in India and the Peninsula.

Colonel Digby Hamilton was a temporary Colonel in the army and the Colonel Commandant of the Royal Waggon Train. He had served under Moore in the Corunna Campaign.

Moore could have appointed an officer to superintend the baggage, pending confirmation by the Horse Guards. Unlikely that a general officer would agree to such a command.

Captain Huxley Sandon, of the Royal Waggon Train, was Baggage Master General under Moore.

Punishing stragglers and plunderers was under the jurisdiction of the Provost Marshal and his Assistants. Usual British practice was to appoint a sergeant the Provost Marshal and grant him the rank of captain in the army in the location he was serving in.

Good hunting.

Ron