Hi shresmummy- thought I would throw my 2 cents into the debate. I am by no means an expert, so take it or leave it. I would agree with annette.xx. I found that E was so overtired that I needed to put her down quite early to break that cycle. It wasn't forever- just until she was out of the OT cycle. So for a few days, I was putting her down for her morning nap after as little as 1.5-2 hours IF she was showing tired signs. After a few days it naturally lengthened as she caught up on sleep and wasn't OT anymore. So for those first few days I really just watched her for tired signs and tried to ignore the clock. Just to note, she wasn't always happy and willing to go down so early, esp the first couple times, but it was generally much easier to get her to sleep if I caught it early rather than late. The other thing I learned is that even when she was vocally protesting a nap, if I watched her body language, she was clearly ready for sleep and this encouraged me to keep going through the crying. For example, she was crying but she was also keeping her head on the bed instead of trying to rock on her hands and knees. Or if she was lifting her head up, but it kept dropping onto the bed. Or she would burrow her head and rub her eyes. All of these things told me she really was tired and just wasn't able to get to sleep.
I told you in another post that I went to the family care center 'sleep school' near me and our sleep turned around a lot after that. In addition to the above, which they helped me recognize and it worked for my LO, they also advised me not to feed E before midnight. They told me (and I know this is going against BW technique) that the best sleep that babies get during the night is the first long sleep- so the first stretch after BT. SO when I introduced the DF, I was interrupting this sleep. In addition, the first stretch is generally the longest so if your LO is waking after 4 hours, the next stretch will usually be shorter than that, if that makes sense, so you get more NW. Eventually E started waking up BEFORE the DF and then I was in the routine of her waking up for feeds at 10, 2, and 6 on a good night. So I stopped feeding her at the 10pm wake up and just resettled her instead. It took about 3 nights of a lot of crying but after the 3rd night she actually slept through. She doesn't consistently STTN but usually she will sleep until at least 5. So after 6 months of 2+ NW I am very happy with that. I know naps are your major issue and I am not sure how your nights go, but I put this in because I think this contributed to us breaking her OT cycle, so it may be worth a try if you are feeding you LO before midnight. Our sleep has gotten so much better so I wanted to pass along what worked for us. We are now on 2 1.5-2 hour naps a day and if she doesn't get a good nap one day or we are out at nap time, I know that I can catch her up later in the day without too much drama.
I just reread my post and I feel like I haven't made any of it very clear so let me know if you want any further detail on any of it. Good luck!! I know how frustrating it can be!