ok that's great do you lintel to cover the 600mm width so no concrete gets to the drain that you pour between first courses? sorry if it's a stupid question
No. Shutter up to the level of the concrete. When concrete set remove shuttering and fill void with 10mm PEA gravel. When setting brick work lay the lintels then, leaving the cavity open.
One question ive got is, "are you stepping the brickwork in from the existing house line". Only asking because the foundation isn't out far enough if its in line with the house. See red line on pic for reference (not to scale)