Richy, reading this thread and trying to make sense of it is like trying to grab hold of water.
You claim to be so laid back. I'm not laid back at all and I've never done that to an employee so I would suggest from that and other things you wrote, you are not 'laid back'. You wrote above about being 'mugged off' yet you don't see your part in allowing that to happen. You say you are the boss yet your employees seem to have the upper hand.
There's been some very good advice given in these 8 pages yet you seem to reject it all and carry on with the same attitude that seems to have led to the problem to start with and not once have you acknowledged that any of it may be of use or worth heeding.
You won't even admit what you did was wrong even if it is to a degree understandable. You wrote that you weren't implying you'd use violence again yet you used that once already. You wrote that you, as the boss, will stand up for yourself when backed into a corner? How will you do that?
It is blindingly obvious to me that you need firstly to admit you need outside help on how to manage and secondly, you would be well advised to listen to the advice of those who have already been the boss and have already employed people.
There really are some excellent management courses and there are also some incredibly good courses about dealing with conflict in the workplace as that type of problem you had is very common. Otherwise, carry on as you are and carry on having these types of problems.
Also, about the employee concerned, you wrote he is a loner yet you want him to go canvasing? Maybe canvasing is just too far outside his comfort zone hence the unwillingness, yes?