That's very high quality footage Andrew.. camera and lens working nicely for you and well processed. Variation in airglow looks good too. When you give up Big Dob observing there's still a career for you in timelapse :-).
Without much knowledge or thinking about it very hard I'd still say the bright object is a very long polar orbiting satellite having a bit of a flare. That would be an unusually bright asteroid and an unnatural change in brightness.
Asteroid that bright would be very easy to identify. You can try here:
http://cgi.minorplanetcenter.net/cgi-bin/checkmp.cgi
I'm sure there was a page where you could more easily list your field and observing time and have it list objects in that field, but the page above should get you there.
This page helps you identify satellites that can be confused with natural objects:
http://www.minorplanetcenter.net/iau...SpaceJunk.html
Phil