Well that is weird. From time to time I have excruciating pain from sciatica and can't bear to drive the family Skoda but I can drive for miles in the Morgans past and present without a hint of pain. I think the most comfortable seats were the Restall versions which were fixed, with a removable squab.
I had a recurrent back problem but find the Morgan seats far better suited to my back than any tintop I've driven, I can quite happily drive all day with only comfort breaks. As has been mentioned I have the seat back fairly well laid back.
Interestingly I have suffered far less back problems since I took up Church Bell Ringing, the reason being that the spine gets stretched as opposed to it's continual compression for about 3 hours a week.
