it may be that all you can really do is try, this is what i did, i held dd off as long as i could in the morning, did half lunch before nap and half lunch after nap, and then we put dd to bed earlier in the night, dd sometimes couldn't wait for nap on those days we did two naps, it took a few weeks to adjust, she also started having early morning wakes, they didn't last, infact everything was messed up, eventally she started napping at midday, we did lunch at 11.30, i wish i knew how to track previous post as many people have posted about this, all the best, i love the one nap, gives you and opportunity to do something, of course for me this is all going to change real soon and this is the bit i am not looking forward to being house bound