Complex sentence: In his time at the helm, he broke the club's transfer record by signing Michael Owen; however, he was sacked in February 2006 after a bad start to the 2005--06 season.
Split into simpler sentences: In his time at the helm, he broke the club's transfer record by signing Michael Owen. However, he was sacked in February 2006 after a bad start to the club's 2005--06 season.