sleepless 23 month old

i have a 23 month old she is my second child. my problem with her is she refuses to sleep.
i get her in routine of nap at 1pm until 3pm then bed at 10pm and she will stay like that for 2 weeks then she will just stop wont nap until 3pm then wont sleep until 12am and if she doesn't nap she refuses dinner and sleeps at 6pm but wakes at 1 pm and wont go back to sleep. she has been like this since she was newborn and no matter how much i try she will not go to bed earlier. she is still breast fed and doesn't self settle very often.
she also still wakes at 4am for a drink. so i am not getting very much sleep and neither is she.
she shares a room with her older sister who is 3 but my 3 yr old is asleep 5 minutes after shes in bed which is 8;30pm.
how can i help her get to sleep and stay asleep. and at an earlier time?
she is not in a cot anymore shes in a toddler bed.