Don't get confused with that D2 stuff Jason, D1's have a single actuator.
You will have to pull the door card off it's fixings but only the area the has the sub speaker if u have one, so that is the outer edge of the door card and you will get acess to the actuator.
It may need just a slight adjustment on it's mounting screws or the the grease inside has hardened, so you can either drill a small hole in the case and splash some WD40 inside or as I did and split the case and re-grease the motor and track then tape it back together and refit and re-adjust that stuff is not a problem for me.
You can go a replacement slave actuator from Maplin's at around £8 or was and fit that, although it's not plug n play you will have to cut plugs off and re solder.
That it job done