Jack -

General Moore's force was mostly composed of the 1st Battalions of the regiments. Most of these units were in no condition to return to the Peninsula six months after they were evacuated from Corunna in January. The initial units that composed Wellington's Army in July 1809 were either 2nd Battalions of the regiments or from units that were in Portugal or Spain but not part of Moore's Army that fought at Corunna.

Steve Brown wrote a superb article on when every British battalion went to the Peninsula and when they left. It is called "All Bound for Lisbon" and can be seen at: https://www.napoleon-series.org/military/battles/1808/Peninsula/BritishArmy/AllBoundforLisbon.pdf

Bob