Fixed Sash 3G with internal beading?

[ectoplasmosis]

I'm looking to fit fixed triple-glazed units into the very narrow (300mm opening) side apertures of the bay windows in my Victorian house, but size them in such a way so that the frames are hidden behind the exterior brick masonry, and only the glass is visible from the outside.

 

This would necessitate the glazing to be replaceable from the inside, to save having to wreck the fabric of the opening if the glass is compromised.

 

I would prefer to use Velfac 200 Energy, but their fixed units require the sash to be removed from the outside in order to replace the glass; unsuitable in this case.

 

Is there anything out there that's suitable? Looking for ~0.8Uw, ideally timber or alu-framed.