Insulating to/from atmosphere in masonry

[LiamJones]

Hi,

 

I need to run 150mm to/from atmosphere. These 2 ducts will need to run through 100mm masonry, 80mm cavity (EPS beads), 100mm masonry, 100mm EPS EWI, Krend silicone.
 

can I just insulated the duct up to the inner leaf, or do I need to insulate the duct all the way through. If I sealed the duct to the inner leaf, the likelihood of moisture being in the wall buildup is low, right? 
 

Pre-insulated 150mm ends up at 172 o/d. I’d prefer to keep the size down, all things being equal.