My 20month old DD has never been a great sleeper. She was EBF to 6months and is a good eater now. She has a good routine - tea at 6pm, 6.30pm bath then stories in a dimmed room, bottle of milk, cuddles and into bed sleepy but awake by 7.30pm. She usually goes to sleep okay but she won't sleep through and often ends up in our bed at 4am after many wakings. She sleeps in a gro-bag and doesn't always seem that comfy in it. She's a very independent, wriggly little live-wire and although she hasn't climbed all the way out yet I am wondering if the move to a big girl bed might help?
From personal experience of a bad sleeper - moving to a bed made things worse rather than better! DS used to disturb through the night however when we tried him in a cotbed he would get out of bed each time he disturbed, therefore being wide awake and difficult to settle again.
Maybe try getting rid of the gro-bag and using a quilt instead at this age, see if that helps?