Complex sentence: Back in Britain, he began his working life as a farm labourer in South Eastern England and then ran a mobile disco before moving to London where he started in advertising as a messenger boy and worked his way up to creative director.
Split into simpler sentences: Back in Britain, he began his working life as a farm labourer in South Eastern England. From there he moved into being the owner of a mobile disco before moving to London where he started in advertising as a messenger boy and worked his way up to creative director.