While I don't know for sure, some vans I have found will have them held by velcro and some have staples while others hidden screws in wall and slots on back of cushion so first off I would closely inspect around the edges, gently try to prise a gap on an edge to see a fastener also for a screw slot job try giving the bottom a hit upwards to knock the slot off the screw head, only need to move about 10mm to unlock.......... sometimes a button cover can be a screw cover as well, they are often just push fit caps............... In my Coromal it had velcro stapled onto the wall and cushion back..... just give it a reef and off it came...