You will be right Pete.
DN1 pattern frames are almost never seen anywhere in developed countries other than in very primitive patterns from the past. It is almost invariably the case that if you do NOT want Hoffman you have to make a special order. The frames that need ends added are pretty well a pre war thing that just refuses to die in the UK.
Have seen a Spanish type with no self spacing but much wider wood, and simply butt jointed.
Have weeded all the old SN1 and DN1 types out of our unit in recent years and consigned them to bonfire. Somewhere in the dark recesses of the attic above the extracting room we have half a dozen fondant boxes of metal and plastic ends if anyone wants them..........