Ok, the v0.2 boards have arrived and work nicely with the USB bootloader uploaded 
Three little pigs:
PCB assembly by Aisler - EU based and priced similar to the Chinese shops, and I’ve been very happy with the bare PCBs before. The assembly process was easy, and would definitely recommend using them in future.
Only one “major” mistake - the KiCAD footprint for the bicolour LED on the front is incorrect. I’d fixed this for another project, and clearly forgot to port it over to this one. Will open a PR with KiCAD as well, a bit annoying. Not a functional problem, but there’s no visual indication of activity. Good to catch at prototype stage.
Next step: finish off the firmware. Thanks for everyone’s input and comments so far, and always open to any other suggestions.