Identify this old folding bike that I got from the tip - an early Dahon?
It does seem to be an early model Dahon OEM or Dahonesque bicycle -- i.e., made in Dahon's factory or cloned from Dahon blueprints, but then sold under another label.

The way to identify an early Dahon is that their bottom bracket is above the downtube folding hinge. This particular model is missing the steering brace that helped make the early models less rickety.



Early Dahon bikes aren't particularly rare or valuable at all - especially an off-brand like yours. It's not as if you had a 0-series Brompton. With your bike, you can tell from the one-piece crank that it was designed as an inexpensive commuter bicycle - what we tend to call on this forum, a Bicycle Shaped Object. Later Dahons with their oversized aluminium tubing are much better than these early models.



Just remember that just because something is one-of-a-kind or rare doesn't mean that it's valuable.