So had a brain fart then figured it out
@JonnyT . Now this is a bit long winded but here goes.
To use the speed limiter you select the assist programs by using the switch on the end of the indicator stalk, you then scroll the menu displayed in the DIS using the right hand thumb wheel to cruise control, select cruise control
on by pressing the cruise control button on the left side of the steering wheel, once that is selected (highlighted with red tick box) use the right hand thumb wheel to scroll to speed limiter and select ok with the right thumb wheel (again red check box). This is now active and you increase/decrease the speed limit you want using the set/- + on the left side of the steering wheel.
Basically it wont let you select limiter unless the cruise is activated, only then you scroll the menu to change to limiter. Hope tht all makes sense, might even video it.