I've noticed something with my insomnia and my smoking

There have been several scientific studies that have found smoking impacts negatively on sleep quality. I'm not just talking about all the warnings on "health freak" sites, which may or not be reliable. But try googling the NCBI study. I believe there are more out there as well.

This seems to be a comparatively recent area of research, but what has been known for years is that smoking reduces the amount of time spent in beneficial REM sleep. Although I don't think this would account for your waking up after one sleep cycle (which is usually about 90 minutes) it might contribute to you feeling a bit tired throughout the day and generally disrupting your sleep.

I'm glad to hear you've taken to using e-cigs at night rather than the real thing - especially as you say you've sometimes burned the bedclothes. I expect you know that a high proportion of fatal fires are caused by people smoking in bed. I live in a 7th-floor apartment. Several families share the apartment across the hallway, and there are many heavy smokers among them. In spite of the building's state-of-the-art air-exchange system, I can still smell the neighbours' smoke in my place. It's especially strong late at night, and I can't say that reassures me!

I'm a lifelong non-smoker, having spent the first 8 years of my life living, eating and sleeping in one room with parents who smoked nearly 100 per day between them, because of the stress of poverty. But I've still had a REM sleep disorder all my adult life, so you can't always draw the obvious conclusions!