I recommend sourcing the covers from here: http://www.classic9leathershop.com/index.php?p=home
you also could send the seats to them if you want or use a local upholstery shop (I have used Fernando at Marlee Auto Upholstery 416-789-1542 and pleased with his work and price).
If you want to keep the seats in Canada, I can recommend Rightway Heritage Trim, although they are located on Vancouver Island. https://www.rightwayheritagetrim.com/
Andy
I used TM Custom Trim. They’re on Steeles just east of the 400.
They re-did the complete interior on my old SC. I’ve also had repairs done on my other vehicles.