Assuming it is a non load-bearing studwork partition, you should consider the following options:
● 35mm x 65mm CLS framing with studs at 400mm centres and half-height horizontal noggins, clad both sides with 12.5mm wallboard and the void filled with mineral fibre quilt (90mm overall width)
● 35mm x 65mm CLS framing with studs at 400mm centres and half-height horizontal noggins, clad both sides with 15mm SoundBloc plasterboard, no insulation (95mm overall width). You could also use 50mm x 75mm sawn regularised and kiln-dried timber instead of CLS (97mm or 102mm overall width). As an alternative you can substitute 35mm x 89mm CLS or 50mm x 100mm timber and increase the stud centres to 600mm, dropping the half-height noggin (115mm or 120mm overall width). This is the typical detail used by the timberframe industry. When you order your door linings allow an extra 6mm to the wall width for skim-finish plasterboard, whereas for joint finishing use the actual width of construction.