Our local upholstery guy can take the vinyl insert out and sew in a fabric of your choice. Was a popular thing to do back in the 80's around here when everything came with vinyl. Here in Iowa, the summer sun would heat the vinyl up to the point it would burn you and the winter cold would freeze your unmentionables off for miles. If you buy a new cover, have it modified before you install it,
Just thinking out loud,
Scott