In April 1760 he was promoted lieutenant-colonel of the 21st Dragoons (Royal Foresters), serving in Germany under Prince Ferdinand of Brunswick.
When his regiment was disbanded on the Peace of Paris in 1763 he was appointed lieutenant-colonel of the 2nd Dragoon Guards.
[2] After the American Revolutionary War broke out in 1775 Manners was appointed colonel of the newly raised 19th Regiment of (Light) Dragoons.
Manners was made colonel of the 86th Regiment of Foot on 20 June 1794 and transferred to the 26th Light Dragoons in 1795.
He had been staying at Southend for his health, and feeling unwell during his morning ride had set out for London alone to get medical advice.