It seems that no one has this problem so its either me or the seat/brackets is/are wrong.
This is in reponse to pete. I have seen old images of the bikes with sprung seats AND rear shocks. Perhaps not needed but there is precedent for having both.
I had/have the same problem... the deluxe tan comfort seat comes with brackets and NO instructions as to how to mount them, and there doesn't seem to be any way of matching the holes in the 'L' brackets with anything on the bike that would be a proper and easy fit. It's a pain in the you-know-where to get stuff like this. It ain't 'intuitive', that's for sure.