Well, as I'm new to the site, I thought I would upload a video of my current level. It was done in one take, so there are plenty of mistakes. I figured that posting a polished video would somehow defeat the object.
This is after about a week of practice, having watched the WikiHow video a few times and the excellent video on achieving left hand independence, which I really recommend: Boogie Woogie Left Hand - from ZERO to INDEPENDENT in 15 exercises (time-lapse) - YouTube
I somehow wish I had posted a video of my level a week ago, because even though my performance is clearly full of flaws in this video, I can assure you that I had zero left hand independence with this particular bass line just seven days ago. Gotta keep practising! And if I make progress, I may well post more videos!