Knee wall studs / roof structure (house retrofit)

[HugoWedge]

Hi all,

I’m retrofitting a 1930's end of terrace and renovating/insulating 2 rooms in roof at the moment.
I've stripped out old wallpaper and opened up sections of a knee wall (lath and plaster) to gain access to the eaves and install much needed insulation. While doing so I exposed a few timber studs which are directly nailed to the roof rafters (150x50mm @ 400 centres) at a height of 1.6m. I thought it would make sense to move these studs back a bit to gain some extra space and square off the room.
It seems logical and fairly straightforward but I'm not sure if these studs (70x50mm) were simply holding the lath and plaster dwarf wall or if they have any structural function. I'm convinced they're not structural but may help to prevent sagging, although there's no indication of sagging on any of the rafters (they barely touch the top of the studs).
I took some photos of the roof structure/studs (attached below) and I was wondering if you could give your opinion on this?
Much appreciated.

 

[HugoWedge]

If anyone has any thoughts on this it would be really helpful to hear. I understand I may need professional advice from a structural engineer but it would be useful to test how likely and feasible this change is before spending significant money on professional fees.
Thanks.

 

[catlad]

It is structural, and even if you took it away you would not be able to square the room off, except for the carpet fitter!

 

[HugoWedge]

Thanks Catlad. Hope you don't mind me asking, what makes you say the studs are structural?
I find it odd that some rafters (above the staircase) don't have any knee wall/studs and span a much longer distance from external wall to collar tie and ridge. I presumed these studs were not part of the roof structure since there's no header and the rafters barely touch the studs (no indication of sagging either), also the knee wall doesn't have any wall below at ground floor.
I wasn't thinking of removing these studs entirely but simply move them back a bit 350mm or 700mm to gain some extra space and incorporate some eaves storage.
You're right, this wouldn't square off the room entirely but the new flooring and external wall would be.