If the SEP client is removed from add/remove programs it should not reapper in sepm console. did you remove it?
for client to communicate with SEPM it needs to have Sylink.xml and it should be of complete install. corrupt install will not make the client to communicate.
For me it seems to be some duplicate id of machine with same name on your network.
If you still want to clean it up.
Call support get clean wipe utility. It would wipe out SEP from your system.