options on internal plaster/finishing kitchen extension

[Crowbar hero]

Hi all,
I'm looking around for ideas regarding the internal treatment/finishing of my kitchen extension. It's a conventional block/insulation/block construction, and I need to know my internal dimensions after finishing so the kitchen design can be finalized.  I know traditionally dot n dab is favoured for speed, however I'd like to look at alternatives as there will be kitchen units hung on one side (and a utility/WC on the other end) - Ideally I'd like to maximize internal space, yet ensure the wall is suitable for hanging.  Would a layer of OSB under the plasterboard pass muster for increased strength for fixing? Can I fix the OSB direct to the blockwork (assuming it's plumb)?  Or would a bond and skim approach be suitable? Would this be likely to be more labour intensive? 

 

One side is obviously existing structure, so I imagine I'll be having to hack the old render off to get a decent base, then make it plumb (it kicks out a bit at the bottom). I could do this with battens behind the OSB (if I use that route)..

Are there any other approaches I could consider?

[nod]

Forgets the dot and dab a fe plaster with sand and cement or one of the bagged backings Such as hardwall or tough coat