it will fit yes mate, but you'll also need the driveshafts from the leon, as well as the shifter and cables from inside the car, the left hand engine mount from the 02M gearbox, the 6 speed clutch and flywheel, and a clutch slave cylinder as they're internal on the 02M and external on the o2J.
lot of work but it'll go if it's what you want. if you've got a leon to rob all the parts from it's not too bad.