Some minis have a ballasted ignition system as standard.
The ballast resistor uses a 6V coil and drops the LT 12V supply down to 6V by using a power resistor (often bolted to the inner wing near the clutch).
When starting (IGN=position 3) the ballast resistor is
bypassed and the coil sees the full system voltage (which will probably be less
that 12v since the starter motor is drawing vast currents). The ballast system
is basically a starting aid.
The 12V coil will not work so well at starting as the system voltage will fall
as the starter cranks over, but 12V coils will produce sparking HT's down to
about 6V LT anyway, so they still work.
One advantage of the non-ballast system is that the wiring is neater and you just have a simple 12V LT feed, rather than all this pos II or III three terminal resistor crap.
Open up the loom approx. 6 inches from the right hand side of the fuse box
Inside the loom you will find that the white wire that comes from terminal 1 of the fuse box is crimped and soldered to the start of the white/pink resistor wire
Run a new length of wire along the loom and solder it to the crimp
Tape the loom back up again and tape the new wire up along the remaining part of the loom as far as the coil
Substitute the new wire for the white pink resistor wire at the coil
Tape off the resistor wire to the loom
Leave the resister live if you think you might change the engine as you might need it again