you don't need a SE-IR, that's what Integrated programmes typically include, but there's no real need for it for a modular student, you can go straight to ME-IR
the order is -
1) PPL
2) ATPL theory - Hour building - Night Rating (can be done simultaneously, no real order here)
3) once you have 150-170 hours Total time (and some 50-100 PIC time, depending on school requirements), you can begin your CPL/ME/IR training. Some schools start off with MEP, ME-IR followed by CPL.. others do it the other way around, really depends on school
4) Once you have CPL/ME/IR, do your MCC (+JOC optional)