Dormer eaves space wall insulation

[BILLDIYNOT]

I have seen some threads related to insulating stud walls in dormer bungalow eaves spaces and some references to VCL but it's not clear for me and I don't want to do the wrong thing.
I have a dormer bungalow where I walk through the back of a dormer bedroom wardrobe into the eaves space, which is like a loft at each end of the house. The eaves space appears well insulated between the floor joists and above them. I can turn around when in there and look at the stud walls that are the walls at the back of the wardrobes. These stud walls do not have any insulation and I believe they can/should have.
1. Do I need to leave any kind of gap between the plasterboard in the stud wall and the insulation I intend to install ? (i.e. does there need to be an airflow at this point ?)
2. Can someone clarify the use, if at all, of VCL in these stud walls for me please ?
3. I have seen mention of wool insulation in the stud wall frame and then covering across the wooden stud frame with rigid Kingspan/Celotex to a total depth of 150mm (no VCL). Is this design application correct and is 150mm total enough ?
Thanks, in anticipation, for your expert advice.

 

[BILLDIYNOT]

Hello. Is the forum still operating or is there a different reason why I have not received a response ? I appreciate that advice in this forum is free and advice, in the past, has always been helpful. Thanks, in anticipation.