There is a socket on the handset, essentially a headphone socket that the one end plugs into and one on the control unit for the mover the same, IIRC it's next to the LED. You are supposed to remove the battery to do this.
The control unit is probably fixed to the floor of the underseat storage behind your battery box.
There's a hinged flap over the electrical connections to the battery and motors and, on current control units anyway, the umbilical connector is to the left of the electrical terminals (under the cover)
Amazing family weekend with old steam engines, classic car displays, market stalls, and full catering and bar. And camping on site - Save £25 by booking in advance.