The floor is currently down about 450 below inner FFL so assume plenty of space for the sub base, concrete, installation and screed, hence why you see soil at that level.
The foundations are trench filled 1+m.
There is then a line of block laid flat to increase the found height, then 4 brick height of brick with a DPC and then another 2 brick height then another DPC. Not sure why 2 DPC's, assume it's to do with the concrete floor.
They have ties around the openings but not within that large length/width of wall, which is why I was confused. I've asked the building control officer for his view on it.
They are a reputable large builder with their own cement mix company, scaffolding, building squasa etc and a couple of million cash at bank, so not a 2 bit firm I would expect to make cheap mistakes. It's a 2 story 130m2 extension rear and side/back with 15 steels to go in, so a fairly large job. I'm also getting the existing suspended floor in the existing house ripped out and replacing with concrete as well as a few other holes in walls etc.
In 4 days they have competed demolition of existing porch and garage, site clearance, inside of house suspended floor ripped out, kitchen gone, founds dug and laid, drainage dug and in and now above DPC level into the superstructure. I've been down with the tape measure each night (as ya do!) and they are mm perfect as per the plan for walls, openings and drainage runs. They reckon 2-3 weeks to complete, which at first I thought they were joking! I thought WW3 was kicking off the first day with the number of people, JCB's and trucks on site!
I'll setup a build thread and anyone interested can follow as I'm taking photos every night.