Just followed the link in my email from Brompton. Be interesting to find out what caused the gears to fail. Three punctures in three days is really bad luck.
give 3 out of 6 failed - sounds like a the rear sprocket change issue and hub gears were fine.
Definitely sounds like a chain pusher issue.
I had it happen once when the little hex bolt dropped out of mine. I think it left me with 2, 4 and 6 (rather than 1, 3 and 5). Happened right at the bottom of the mega hill on my commute.
I was very lucky in that the bolt came out of the frame but stayed attached to the chain pusher- so when I finally made it back home, I stuck some thread lock on it and it's been fine since.