Complex sentence: The tanks and small amount of motor transport belonging to the 4th Armoured Brigade however had been held up even further back, they had been stopped in Carlentini by a destroyed bridge, and the 4th Armoured Brigade did not start moving again until after 19:00.
Split into simpler sentences: The tanks and small amount of motor transport belonging to the 4th Armoured Brigade had been held up even further back. They had been stopped in Carlentini by a destroyed bridge, and the 4th Armoured Brigade did not start moving again until after 19:00.