Rach - mine took about 3 days with tori and then with charlotte I swear to you my body knew she was tiny and needed it nice and fast and it came in full force within 18 hours of birth! Even the midwifes etc were surprised but pleased as it meant she actually didnt lose ANY weight after birth, just put it on straight away, lucky coz she had no weight to lose at 5lb 3oz!
Time will tell though