I have also finished 3 brigadiers to lead my infantry. The riders are all from Black Hat. They are nice sculpts, though chunkier than Dixons and Warrior and can't be mixed. I decided to change the horses, 2 from Essex and 1 from Minifigs. The Black Hat horses are very large and do not match with the others.
I've finally made a start on some of the horse. The first completed are the Royal Scots dragoons on their grey horses. The figures are all Warrior apart from the drummer which is an old minifig sculpt, matches in okay. My experiment of trying to bend the arms failed as the metal just snapped, hence having to also include the trumpeter.