Kilted Ginger

If its dot and dab better using 2 inch size 10 screws and rawlplugs, the plasterboard fittings that guru suggested but are better in cavity walls with double layer plasterboard.

I'm assuming the cupboards have the offset metal plates on the back of them, is so 1,1/2 screws may be enough, if its the type where you fit a wooden strap to the wall then you will need the 2 inchers.