I have started to realise that using the TA recommended by my brother in law was not the best decision. He has drawn the footings as below (300mm strip)
My plan is to increase the depth of the footing by another 225mm. This means I would have effectively 3 courses of block below FFL. I want to avoid having to put soil pipe through the trench and ideally want to have the pipe go through the blockwork via lintels. Otherwise, I need to get some oversized pipe in place for when we pour (next Friday).
The invert level of the lowest IC is 550mm below FFL, so I cannot go too shallow, otherwise, I will have to put the soil pipe through the trench footing.