I took my Brompton up to Portapedal to have Tom take a look at the brake cable issue that I've been having (where it's been knocking the chain off of the chainring when folding) and to also get it prepared to race in the Brompton U.S. Championships.
Race preparation consisted of removal of the rear rack & fender (which required an alternate mounting point for the dynamo-powered rear light) and installation of the lightweight Kojak tires (kevlar bead). Tom handled this pretty quickly, which is something you would expect from a pro!
The brake cable issue was a little trickier to diagnose. We kept comparing it to a similarly built new Brompton that they had in stock and really couldn't tell much of a difference. We ended up trying to zip-tie the cables in slightly varying locations and also adding some grease to the outside of the brake cable (where it contacts the loop on the front part of the top tube) to try to get it to not catch as easy. Seems to have worked!
The Brompton does indeed look slightly different with the rack removed and is much more difficult to move around when folded! I've still got to take the mudflap off of the front fender!