Ok, not sure if this will help or not, but after the time change in the U.S., it took my daughter (18 mo) several days to get back to a decent bedtime. She has had a 7 pm bedtime pretty much from birth, with the every so often early night from a short nap. But even if she didn't nap long that first week after the time change, she wouldn't fall asleep until 8 pm (the old 7). She's now back on track at night. Since you don't really want to cut the nap, could you give it a few more days and see if she eventually comes back to about 7:30?