Now if you go to the left and right bottom corners of your Toblerone the weight of the roof goes vertically down to the load bearing INNER skin of your exterior cavity walls.----

The roof trusses sit on a timber wall plate at the top of the inner skin of your external walls. Do not play with these walls as they are LOAD bearing.----:eek::eek::eek:

But as long as the roof truss is sound and the bottom chord on the truss is present then all the load is straight down through the load bearing wall(s) isn't it? So as far as the wall to be removed goes it shouldn't make a difference: If the wall to be removed was giving strength to the outer wall at all it'd have to go all the way to the top of that outer wall after all.