+1 on a replacement from a local breaker. It's likely to cost you buttons as interior and trim are usually the last things they sell and are the least recyclable/have the lowest scrap value.
I bought a pair of front seats for a rover 100 to fit to a friend's series Landy for a tenner a while back. Cheaper and more effective than the detergent to shift the diesel from your own seats by a long shot.
"Just because Science doesn't 'know everything', doesn't mean you can fill in the blanks with whatever fairy story most appeals to you" Dara O'Brien