If you've been looking for a Suwe Cortina rear derailleur for your mid-1950s bike because you've been there and done that with Campagnolo, now's your chance
http://matuzmaster.hu/
Geoff Butler's description appears to be excerpted from the Disraeli Gears site, which has a bit more information on this rear derailleur
http://www.disraeligears.co.uk/
No relation to seller; I've purchased parts from him several times..... Peter
Peter Brueggeman
La Jolla California USA
4peebee(at)peterbrueggeman.com