What you are having is a string of False Awakenings. This is a common experience for LDers. It is also common for FAs to be short. Mine also average one minute in length and also often involve hearing people walking up my stairs, into my room etc. I think your problem could be that your brain has finished its REM. I don't know what time you are going to bed but if you are waking up at 4.30am every morning then your brain is getting into the routine of that being your normal wake-up time. I'm thinking you would find the CAT method very helpful. You obviously have good WILD skills but you need to be doing a WILD when your brain still has some dreaming to do so that when you become lucid it is in a proper dream and not just a few measly FAs.
The Cycle Adjustment Technique is here
http://www.world-of-lucid-dreaming.c...technique.html
Feel free to PM me and let me know if you have any success!