I am just finishing up a ground up restoration on a MK 1 Morris.  Ordered new seats from Newton Commercial, it took exactly 4 weeks and they arrived at the front door.  They are great, match the back seat, are much more comfortable, have a nice curved back that is taller and recline. I can't be happier with them.  Easy to get in and out of and took about two minutes to install.  

James

I have Corbeau Sport seats in mine. Very comfortable, yes you can still get into the back seat but a little tighter. You do have to buy or make the mounting brackets. And they have a head rest which was a requirement for me.

Jerry

I put acura integra seats into a MK 3, but not sure how they'll fit with the door bins.  You could drive to a junk yard with the passenger seat out and ask to try some seats. Call ahead and see if they'd let you do this.

 

if your  original mini seats don't have the head rests, you're doing a very smart thing. You could snap your neck in an accident. I've used the fiero and miata seats. I just bought ford mustang seats. they match the interior with the horizontal stripes. the upholstery is quite expensive, atleast n my area. so try to find something that can bolt in. basically everything is going to require fabricating a inbetween from mini floor pan mounts to seat mounts.

I've heard of Acura seats being used, Miata seats also.  Custom mounts/frame required of course.

Red Riley has some nice seats going....hopefully he'll post a couple pics

Here

Hello. I need to consider an upgraded seat in my MK 1, as the wife gets a sore back after a few hours with the original seats. I was hoping something from a modern car would work well ( fit and height) so any suggestions welcomed. This way I can start looking for something better for the long drive. A cross Canada tour is possible if I can get the seat issue sorted. Thank You