Ian,

An Adjutant was a commissioned officer. In the 18th Century and Napoleonic eras the post of Adjutant was seen as administrative, almost clerical, role and was frequently filled by a former Sergeant Major, after commissioning, normally holding the rank of Lieutenant. Are you sure that he went to the 88th Regiment as their Adjutant prior to being commissioned? He could not have been the actual adjutant, but might have temporarily acted as one. It would be more likely that he was the Adjutant of the 88th Regiment after being commissioned.

In the modern British Army the Adjutant is a more prestigious post, normally a Captain. He acts as an aide to the Commanding Officer and is particularly responsible for discipline and personnel matters, assisted by the RSM. Most British Army Generals will have been Adjutants earlier in their career.

Rod