Complex sentence: Rain storms and confusion caused the British main body to partially lose order and break up with thousands straggling and 500 captured by pursuing French dragoons with hundreds more stragglers captured by Franceschi's cavalry on the 10th and several hundred more on the 11th.
Split into simpler sentences: Rain storms and confusion caused the British main body to partially lose order and break up with thousands straggling. Some 500 British were captured by the pursuing French dragoons, with hundreds more stragglers captured by Franceschi's cavalry on the 10th and several hundred more on the 11th.