I agree with Nikolaos and the Colonel, during the Waterloo campaign grenadier companies were not detached to form 'grenadier battalions', but, as Nikolaos says grenadier and light/voltiguer companies could be temporarily detached for specific tasks.

One instance of this at Waterloo was the Anglo-Allied defence of Hougoumont, the light companies of the four British Guards battalions present, the first company of the Hanoverian Feld Jaeger Corp, and fifty men from both the Luneburg and Grubenhagen light battalions were detached from their parent battalions to form the Hougoumont garrison along with the whole of the 1st battalion 2nd Nassau regiment.

Most of the other companies of both the 2nd battalion Coldstream Guards and 2nd battalion 3rd Foot Guards were, later, sent to reinforce Hougoumont but the initial deployment was of the light companies only. Only the light companies of the 2nd 1st Guards and the 3rd 1st Guards were sent to Hougoumont, the other companies of these two battalions remained on the ridge.