Yes there are people who need to lock their brompton and can‘t take it everywhere. If you are one of those persone you can continue reading: I was searching for an elegant solution for a lock mount. Here‘s what I found and came up with in Detail, because I couldn‘t find detailed information/pictures about it:
Brompton C-Line 2sp,
Abus Ugrip Bordo 5700/80
You need to flip the rear frame clip, Since you also flip the spring you need to put some washers inbetween so the release sits in the middle. Voila, beautiful and nearly hidden lock mount.
by RealHotzenplotZ