Just tried aligntovector, using the vector from the camera to a pivot in front of the camera and that has the same problem. . .
Actually, just checking again, AlignToVector does seem to orientate all the quads in the same direction, but that orienation varies with the direction you are facing, so they aren't always vertical. However, thinking of the senario I'll be using them in this might be okay.
I guess that getting them vertical might be as simple as setting their roll to the cameras yaw after doing the aligntovector, but maybe not. . .
I'm still open to anyone else's ideas / suggestions as usual :O)