Douglas produced 'pannier frames' for the Dragonfly. They were only intended to carry a pair of pannier bags - so, having just one spreader tube and being only slightly higher than the mudguard, it was easy to damage the paintwork on the 'guard. When I rebuilt my 'Fly, I made a modified pannier frame that was an inch or so higher, and had 2 more spreader tubes - making it a much more sensible carrier (see attached photo).
Regards,
Eddie.