Weaning toddler of milk at night

15 month old… Weaning toddler off milk at night is it best to go cold Turkey? He usually falls asleep in his cot drinking a bottle but I’ve removed that bottle I now give it to him before he gets into the bath so he’s still having the milk so he’s taking about 35 minutes to fall asleep without the bottle he uses the dummy instead he would sometimes wake in the night for 1-5 bottles of milk in the night to get back to sleep but I’ve stopped doing this the last 2 nights he’s waking up for 3 hour periods upset and finding it hard to go to sleep without the bottle how long did it take your little ones to accept no bottle at night???