Hiya - so sorry I seem to have missed your reply somehow!
Can I double check - you say sometimes she is doing 5-6 hours A time, but the EASY in your original post is:
Wake: 7.30
Nap: 12.15-2.30
BT: 8.00
That's an AM A time of 4.75hrs and a PM A time of 5.5hrs. So can I ask - is this what she is still doing?
If not, can you post her current EASY - I need to see what times she is waking, napping & going to bed.
If she is still doing the above routine, then IIWM I would increase her A time in the AM a bit. Perhaps start with 5hrs and if she's not ready to sleep try 5.5hrs i.e. nap at 1pm I found that as the nap went later & the AM A time increased, the PM A time actually reduced a bit & BT stayed the same. I also had to start capping my DS's nap at 2hrs max at around 15/16 months old b/c we got early waking if I let him nap for longer. It might be something to consider if the later nap doesn't help.
So your routine might eventually look more like:
Wake: 7.30
A = 5.5hrs
Nap: 1.00-3.00pm
A = 5hrs
BT: 8.00pm
Can I also ask if you nurse to sleep at every night waking? And can she settle to sleep independently at nap/ bedtime