I have 2 A-Ds...a Vent Noir II (same vintage as the E-bay frame you reference), and an older A-D SL. The Vent Noir II is full 531 and takes a standard headset. The A-D SL is not 531 and has the Austrian headset (with English BB). The headset on the SL is nothing special, but has proven durable with the occasional overhaul (new bearings, etc.). So one option might be to keep an eye out for an inexpensive A-D S or SL (or comparable Puch model of the same era) and use the headset for your SLE.