In reply to James Malloch:
I had a cheap folder, which I used for a couple of years to commute into London, about 8 miles a day. It rode quite well, but the components were made of cheese and hard to get replacements for as they were all a bit weird. Eventualy, the rear rim split open, jamming the wheel, and a new wheel wasnt economically available.
The fact is, logic says that a folder should actually cost more than a solid bike, so the rule of "buy cheap, buy twice" is even more true.
I did love the freedom a folder brought, and would have bought a Brompton replacement without hesitation if I'd not been about to change offices to Reading.