Randy, you are correct about TR2s having "dedicated" hubs for wire wheels as opposed to the adaptors used later, but that doesn't help with the clearance. It's the up-and-down motion that one needs to worry about, and the knockoffs will extend out to or even a bit further than a skirt. Odds are one big bump would be enough to destroy even a skirt with a cutout. If you look at pictures of, say, various older Jaguar saloon cars, you'll see that those with knockoff wire wheels do not have skirts.
Hard to tell for certain at this angle, but it looks to me as the knockoffs on this car do protrude well out into where the skirt/spat would be: