As with most things Morgan, the seats have improved little with 100 years of development.

The folding mechanism does at least give some adjustability now, but the seats still won't suit many bodies. Aero seats have no adjustably and imho are incredibly uncomfortable. The new (expensive) sports seats are a step forward in the trad cars.

Possibly Morgan buyers have too high an expectation of actually being comfortable nowadays!!

Even modern cheap tin tops have comfortable adjustable seats and anything a bit more 'exec' has infinitely adjustable electric seats.

Morgan seats aren't really long enough to provide support under the back of the legs and theres no lumbar support, the angle of the seat base is too flat and the foam is hard. But apart from that…………………

The Allon White foam upgrade is good. Shaun can even build you a custom seat if required I believe!!
I'm sure the seat base angle could be changed with the addition of a fillet piece under the mounting.

A cheap and easy change can be made by inserting a piece of foam in the space behind the lumbar area at the bottom of the seat back. You can get your fingers in to the space behind the leather/foam and insert a support, in the same way the inflatable bag lumbar support fits, but a minimal cost.

Sadly, part of the car seat problem is probably down to body shape and poor posture in everyday life, exacerbated by 'basic' car seat design.

I've taught Pilates for many years (my wife is a teacher and has a Pilates studio), and postural re-education is the thing that makes a huge difference.