Wits end with window reveals

[jimbo5050]

I am Building an extension. The exterior walls are constructed from concrete blocks with an inner leaf wall constructed from 95mm W/W timber, lined with 12.5mm plasterboard. There is a 25 mm airspace between the exterior an inner leaf walls.

There are four window openings and two door openings.
How do I construct the inner leaf around the openings in order that I can line them?

I was intending on using ply board as a lining material on the reveals as opposed to plasterboard but I just can not decide where to position the timber framework in relation to the exterior block work and how the lining material for the reveals is fixed around the block work opening.

Any info would be gladly received as I don't seem to be able to find solutions in the DIY books.

 

[masona]

You a piece of timber stud on the return inside the cavity section with the dpc against the brick wall.
The picture is not quite right but give you some idea.

You could have look at the Australia website for info maybe, I used to fit all internal plywood studding inside the brick wall which is a Austrialian design for labour saving instead of inner leaf brickwork wall.