This has been going on for months, though we do get a few nights here and there that it doesn't happen.

DD has a good routine, especially on daycare days. We do the same thing every night. She has dinner, has a bath at about the same time each night, then I give her a bottle. She usually dozes off on the bottle but then when it's finished she'll wake up, so recently I've increased the amount in the bottle from 200ml to 300ml. She still finishes it and wakes up and then decides that it's play time until about 9:30-10:00pm! The only way we can get her to sleep before 10:30pm often is to take her for a drive...we can't afford to do that all the time but she just has so much energy.
I know that she's teething at the moment so I give her pain relief, but this happens even when she isn't teething.

I thought routines were meant to help kids sleep better, but it makes no difference to DD if she's had a normal routine or a few days where her routine has been messed up.

Both DH and I work full time, DH has just started a job that means he has to leave the house at 6am so he needs to be in bed by about 9:30pm at the latest. 10:30 is usually my cut off.

I've also noticed that if DD has a rare night where she goes to sleep before 8:30pm, she'll sleep all night until I wake her up at about 7:30am but if she goes to bed later, she will wake up at about 4am.

I don't know what to do. Please help.