I have added this battalion of 1st Guards to my Peninsular British army. They will represent one of the brigades of the first division (and themselves in battalion level games!)
So a bit of history for the curious. The 1st Guards were raised by Charles II in 1656 and are one of the three British guard regiments (the other two being the Scots Guards and the Coldstream Guards). They were with Moore in the Peninsula in 1808, and returned to fight under Graham at Barrosa during the attempt to lift the siege of Cadiz in 1811. They stayed in the Peninsula to fight in Wellington's army as he drove the French out of Spain and pursued them into France.
It took a bit of research to get the colours sorted but I think this is right. To my understanding the Guard regiments, instead of the traditional Union Jack "King's Colours", flew the burgundy flag, and the Regimental Colours were represented in battle by one of the company flags (which confusingly looked like the traditional King's Colours) but with the company device in the centre (in this case the Tudor Rose of the 2nd Company). So the effect is that the colours look as if they are reversed.