Complex sentence: Although the Germans were in an easily supplied and extensively fortified position and had repelled the Allied force, French troops were advancing from the north and the east towards Kamina unchecked and a British column was advancing on the station from Kete Krachi in the west.
Split into simpler sentences: Although the Germans were in an easily supplied and heavily fortified position, and they had experienced success in repelling the Allied force, French forces were advancing from the north and the east towards Kamina unchecked. At the same time, a British column was advancing on the station from Kete Krachi in the west.