Is Mick Carter Robert Palmer's former manager and Mick Cater of What Management the same person?

No, it no longer exists. Between late 2003 and 2004, Mick Carter lost the contracts of the majority of his known reputable clients, and he could not continue to function financially on the revenue of his lesser known clients and start-up bands that he represented. His unprofessional behavior and escalating substance abuse problems prompted his tried and true clients to seek other management. Mick Carter Management officially closed it's doors in mid-2004 due to lack of operating costs.