I'm just about to embark on this, builder has fabricated the stud wall with
3 x 2 set just off the 13" brick wall. Perceived wisdom is to squeeze the 65mm celotexlike boards in between the studs and flush with them and fix plasterboard over this. This makes sense in that the plasterboard gains some support and is what the insulation manufacturer recommends. From an insulation point of view wouldn't it make sense to have an thinner air gap either side of the insulation as the thinner gap would be less likely to transfer heat by convection currents?AJH