Maiden voyage today. Nothing fell off and other than a spoke catching on the front brake calliper it performed admirably. I bent the spoke in a bit to resolve that but the caliper is a fraction of a mm away from the spokes and I can't see a way to move it out any further. A quick Google indicated it's a common issue with TRP Spyres so it might be something I need to address.
Other than that it feels really nice and I'm pleased with how it turned out.