OK girls, I've just read a few more reviews, and I've decided to abandon the instructions.
I'd already noticed last night that the placket was looking bulky, and the pleat was going to be a faff. So, I've unpicked the plackets, and will use a different technique, which hopefully should lay nice and flat. The pleat? Well, I don't know how that will behave, most people hate it anyway, so I may leave it off the next one.
Jessie