The only option you realistically have if your seat is not repairable is to find another in better condition.
The seat covers are not available anymore and the materials/colours used are not available in an exact match. Obviously you will be able to match the leather, red stitching and red piping pretty accurately but the material on the centres will be impossible.
I have had all of this with my Mini 25 seats and am always on the look out for better seats or covers.
Any trimmer will be able to make replica covers on different seats or even your original frames but they will never look right in my opinion.
I was considering replicating my 25 seats in grey leather with grey alcantara centres and red piping on some Rover 400 coupe seats but keep changing my mind and wanting to keep it original.
Have a look out on eBay, good seats come up relatively often
Ben