OK, so I did it. I rode around Tooting with my left leg flailing to turn the pedal over.
Take 2: Removed reflectors - went a lot better, but still taking a couple of attempts to get foot in
Take 3: Set off without either foot clipped in.
When I finally got a chance to stop, I got it sorted, but I still can't get my left foot in without looking. The SPD cleat on my shoe helps to catch the lip of the pedal, but stops me sliding it smoothly in. But it works very well. Felt so natural that, when I stopped outside my house, I tried to release my right foot with a twist
Now - how do I tighten the straps while riding along?