Take your flywheel to an engineer, and get them to modify it to accapt a 200mm Lseries Pressure plate. There is an off-the-shelf 200mm 18spline clutch plate that you can get. It could be from a primera. this will never slip. The 180mm plates work fine with stock engines, but if you start to make any proper torque, there aren't up to it.

In my experience we took a 60 series 5 speed box out of a 1200 coupe with A14 and replaced it with a 56a 4 speed off an A12 No clutch changes straight in.

It depends on what type of 5 sp you have.

The 60 Series are an 18 spline.
The 63 Series are a 24 spline.
I do not have info on the 56 series; however, I assume it is an 18 spline.

Once you identify your transmission, you should easily be able to procure the appropriate clutch kit, (throw-out bearing, bushing, clutch cover/plate and clutch alignment tool).

got an A14 with a 5speed in my 1200 ute and was wondering if the A series clutches are all the same or what and if it is different when using the 5 speed.... i need to change mine. cheers