Craft and upholstery shops sell vinyl repair tape also. Looks like black electrical tape but much stronger. The rolls I use are about 3" wide. I use it to patch vinyl covers on mattresses and seats at work. It stays on a long time. When we get too many tears then we send it out for recovering. I have a split on my Mahindra seat also. I'm going to bring home some of the tape from work to patch it. I also use a towel on the seat. As a last resort you can buy replacement universal seats at your local tractor supply store and adapt to fit your mount bracket.
I like the repair tape idea. Till now have been tipping seat forward. Did get a new seat from Tractor Supply as a gift last year. Turned out the seat back was not high enough. It killed my back. I returned to store.
Cheers Coffeeman