In "The History of the Rifle Brigade", Willoughby Verner describes how the ad hoc 1st Battalion of Detachments, made from soldiers and officers of multiple regiments who had become stranded with the evacuation of Coruna, fought for the first time near the village of Grijó (Vila Nova de Gaia):
The infantry of the advance guard consisted of the Rifle Company of the 1st Battalion of Detachments, the Companies of the 43rd and 52nd Light Infantry and the Light Company of the 29th Regiment of Foot, the whole under the command of Major Way of the 29th. Cotton with the British Cavalry came in touch with the French at dawn on the 10th, but [Major-General] Michel Francheschi  had some infantry with him and Stewart's Brigade was delayed and did not come for some time; Francheschi thereupon fell back and joined [General] Mermet at Grijó. On the 11th Wellesley ordered [Major-General] Hill to endeavour to outflank Mermet's position on the east whilst he with [Major-General] Paget's Division advanced. In the afternoon the Light Companies of the 1st Battalion of Detachments attacked Mermet but met with a stiff resistance and lost not a few. Wellesley now ordered the King's German Legion to turn the French left and the 16th Portuguese to turn their right and with the rest of Stewart's Brigade renewed the attack on the wooded heights in the centre above the village of Grijó. Mermet thereupon withdrew..."
^ General "Michel Francheschi" is usually spelt "Michel Franceschi"
^ The source is not clear if this Charles William Stewart's Brigade of dragoons or Richard Stewart's Brigade of Infantry . According to Glover, the 1st Battalion of Detachments belonged to Brig-Gen Richard Stewart's brigade.