Tricky with having to drop the nap cold turkey but when my LO was having bad NWs at this age we dropped back to 4.5hrs morning A time and she pulled some lovely long naps. Also I would run in and give her milk at 5am so as to get her back to sleep until a more reasonable hour.
So we would do something like
6am awake
10.30am nap - she would go as much as 3 hours!
1.30pm awake
6pm asleep for the night.
I didn't really do bedtime earlier than 6pm - but nights definitely got better with having a good long lunchtime nap.
Honestly though, if she's going to bed at 6.30pm, a 5.30-6am waking isn't really an EW as such - it's a good 11-11.30hr night! So to get a later morning you're going to need to move bedtime back, gradually. Not easy when she's young for one nap and nap lengths are a bit erratic.