Complex sentence: Malcolm Allison had a strong recent record as a coach, having won trophies with Manchester City as an assistant to Joe Mercer, and had a flamboyant personality that was something of a change for the club, who had always previously had something of a conservative image.
Split into simpler sentences: Malcolm Allison had a strong recent record as a coach, having won trophies with Manchester City as an assistant to Joe Mercer. Allison, or'Big Mal' as he was nick-named in the press, also had a flamboyant personality that was something of a change for the club, who had previously enjoyed something of a conservative image.