Without spats, your feet are going to get soaked - even with spats (and fenders) they'll get some wet. And in a beating rain, you'd want leggings.
Can't keep all the water out of your face, either, and some is going to run down your shirt.
I don't face commuting on a bike in the rain. It's been a couple of years, but from Germany I ordered Vaude Valdipino ponchos for me and my daughter.
We use them for emergencies, and have used them a couple of times. It takes up about 2/3 of the small sackville trunk
No offense, but both of them together were still half the cost of the Carradice.
They're similar in that they're tent-like and cover the bars - there are hand loops inside.
They're also made to go over a helmet, seem to have plenty of room, a drawstring closes them around your face, and they're cut for peripheral vision.
Last time I went out in pending rain, though, I carried a Marmot light "pro" gortex rain shell, had to use it, and it definitely is more closed and sticky than the poncho, I just wore it for a retreat partway home, and bypassed the hood.