Complex sentence: The Lads make a hasty-and trouserless-departure in Bob's car; but they walk back into Terry's flat to find Thelma and Terry's sister Audrey there, with neither Bob nor Terry able to explain the absence of their trousers !
Split into simpler sentences: The Lads make a hasty-and trouserless-departure in Bob's car. They return to Terry's flat safely only to find Thelma and Terry's sister Audrey there, with neither Bob nor Terry able to explain the absence of their trousers!