Back on the road,
Join Date: Feb 2006
Assuming this is a GTV, there is a cable running from the plastic release handle down to the latch mechanism at the base of the seat. The cable is swaged onto a thin bit of rod which is in turn fitted into the handle. The way the rod is retained in the plastic handle is really poor, and could have popped out.
You can remove the plastic handle by lifting it up, and there is a philips head self tapper which holds the handle in place.
Once the handle is out, you can potentially use a pair of long nose pliers to locate the rod end, and reconnect it.
No idea about the end of the cable at the base of the seat, it's probably just as likely have disconnected it self from the latch mechanism. Checking the handle end is easily done, only takes a few minutes.