Spokes swapped over, probably took 2 hours with a break, was easier than I thought, and I was a little disappointed when it was finished, although I was crouching/kneeling on the floor which isn't great for knees and backs (or floors).
I one thing I didn't read about was how easy it is to drop a nipple into the rim, and have to try and shake it out, but after 5 or 6 I worked out how to flip the wheel so the nipple just falls out.
Ideally have a few extra nipples/spokes even if you think you don't need them - I almost stripped a couple of them with the spoke key, and will have to see how truing goes but I may still need to make an emergency trip to a bike shop for replacements. So Sundays probably aren't the best days to do something like this. (today is Sunday)
All of my spokes were too long to just tighten by screwdriver - they would still be loose by the time the top of the spoke was pushing the screwdriver away from the nipple, which explains why I thought I needed a special screwdriver when I was looking down on them last week.
I probably overtightened some of the spokes early on, which meant that some of the spoke threads on the other side wouldn't even reach the nipple, but tightening the spokes either side usually solved this.
So now I have replaced the rim, but probably have one hell of a truing session this afternoon. 8-)