What time do you actually put her down into bed, assuming you are wanting her to be asleep at 7? If she has been taking say 30-45mins to fall asleep, then are you putting her in bed 30-45mins before you want her asleep b/c you know this is how long she will take to go down, IYSWIM? If so, then I would say that's too early & she probably isn't tired enough, hence it may take even longer for her to go over than your planned 30 mins IYSWIM?
I usually put my LO down 10mins before I want him asleep. If I did it any earlier he'd shout, call, jump & probably cry, and he wouldn't be asleep until probably 10mins AFTER I originally wanted him to be! I have to say though, I think we are actually just approaching the point where my LO is UT with a 2hr nap & 5hr A time to BT. For the last 2 nights we've had BT resistance & today we got an EW too. SO I am waiting a few more days & then I'm probably going to cap his nap again, so its 12.30-2.15 & try the 5hrs A to BT & see if it helps.
So if the BT resistance carries on for your LO, it may be that after a 2hr nap, a 5hr A isn't enough. Or a 2hr nap is just too much day sleep. In which case it might be something you need to consider too.xx
Oh & BTW I think 12pm nap sounds like a good plan.x