Quick update, have the joystick working as i wanted it, and using the values I use with the keyboard.
I purchased the virtual control suite as it has PM actions included, which Ive used to make this work.
1st add the "VCAnalog Joystick PlayMaker Updater" script to the joystick, and add this to Get Property, store the Vector 3 as x,y,z, Ive multiplied the Vector 3 by 10 to match the speed used when using the keyboard.
Then used these Vector 3 values for the tank forward, backward and rotation, which was rotating two fast so divided this by 10 to slow it down.
Ive done the same for the turret, just need to sort out the fire button, but pleased with progress.
Andy