personally a shed/timber build isnt worth looking at, they are used by selfbuilders/amatuers as there are quicker and easier to manage than a traditional build. inferior though.
Proper brick and block with a 200mm cav superior in every way.
its just not pointed is all, if you want it to be pointed (better for air tightness) ask the brickie to make sure it is. Some sites its not pointed as its not seen and plastered over anyway.
if its the the inner leaf the tie is on the wrong side ?
Well, you could make a feature of the wall/pillar and put the new RSJ on the outside to save the cost/expense/hassle. It wouldn't make the pillar that much bigger and would save you a packet.
take some ideas https://www.houzz.co.uk/magazine/how-to-work-around-a-structural-pillar-in-your-kitchen-extension-stsetivw-vs~76437319
it doesnt look that bad, acro the lintle in the door and a couple strongboy on the flank wall.
I'd question why the steel in the first place and leave the corner as is, what is it going to be carrying ?
well if its not seen, then i would use 75mm-150mm mixed clean. will be easier to fill. Also the 3mm gabions tend to bulge easily the 5mm are much better. Dont forget to put the tensioner wire in the middle when half filled.
if the gabions need facing you can buy them with an inner mesh that holds 100mm of gabion stone, the rest behind it you can fill with anything that wont fall through the mesh that is clean, ie no dust.
can be done using twist nails and a twist nail gun. Will void build warranty as the truss calcs will no longer be valid if BC catch you without a drawing from an SE telling you do it.
Structural items cane be messed about with lightly.