My handbrake stopped working yesterday

Speaking to my dealer its obvious that its not covered under warranty and so I guess its time to get my hands dirty!
I've taken the easy option first...lifted the "boot" floor to check the cable at the rear of the car and all seems intact. Operating the lever shows no movement to the cable going to the compensator so looks like the cable has snapped or the clevis pin on the lever has failed.
The big question is......is the mechanism accessible from under the car by the side of the gearbox or does it mean doing it from above which entails taking the transmission cover off? If the latter, I'm guessing that the seats need to come out to take the propshaft cover off before the trans cover can be lifted? Anyone got any tips?