So I've just brought some 40mm front 40mm back HnR lowering springs was just wondering do the back springs sit on the axsuls or are they on shocks

Are you thinking of coilovers?

Lowering Coil Springs will sit much like this.

& then there is a ARB fitted here.

Are you changing the dampers?  and how old is your vRS?

 

Picture from google images of an Australian Members vRS.