Thanks guys for all your useful messages. I'm pretty sure the wall is
non load bearing as the 'studs' are attached to a 6x2 beam running
across the rafters (at about head height) which is bedded into the
walls each side of the house.

I think probably the best course of action will be to install the 6x2s
in between the 3x2s and attach them to the walls with hangers. Would I
require an inspection from the builder officer for this, even though it
matches with the rest of the room (and the house come to think of it).


Though to be on the safe side I'll probably be looking in the yellow
pages for a structural engineer tomorrow!

Thanks again.