I was going to give you a simple yes, because it doesn't matter where you break a circuit it will stop current flow. BUT, Having read your question again, I'm not certain of what you are disconnecting. If you are taking every wire of the batteries negative terminal no problems, but if you were only referring to the movers negative wire, then that is not so good, because the other negative wires left attached to the battery will almost certainly include some negative connection to the caravan's chassis, and the danger is if the movers negative wire touched any metal work it may still be electrically connected to the battery negative, by thinner wiring. This could cause a fire if the movers negative touche exposed metal and the mover is turned on
It is more conventional to arrange for disconnection of the positive or both poles simultaneously.
This is particularly important when dealing with mains appliances where there is a real danger of electric shock. If you disconnect the neutral but leave the live connected, then although there is no current flowing, the appliance will still be connected to the 230V mains and if you touched almost any exposed metal on the the potential could find a route to earth through you.
I suggest you follow convention and arrange to disconnect the positive terminal of the battery. This would make more sence to any subsequent owner who may need to work out the wiring.
