The single flag insignia was the one used when the rank of Colour Sergeant was created in 1813, however it continued to be worn well into the Victorian era. I have photos of CS in the Crimea wearing them. The crossed flags was adopted later, I think in the 1870s, certainly used by the Zulu war. There was a Royal African Corp which saw sevice in Senegal during the Napoleonic period. It was however a punishment battalion, west Africa being one of the worst possible postings due to disease (around 25% dying every year from sickness)so it was garrisoned by military prisoners. Infact in 1810 the RAC planned a mutiny which was however detected and stopped by executing 25 and sending another 25 to Sierra Leone which was even worse.