For those who have inadvertantly locked their seat on without reconnecting the cable release rather than the hump, you will need to approach with a slightly different style but the procedure is much the same.
The seat has a guard around the latch to prevent getting at it from the right side of the bike. That is why Slade was unsuccsessful with my hump removal method.
See this photo. It shows the moulded latch hider. Click for larger view.
To defeat this obstacle, you need a piece of wire marked at a 20cm point with a 90 degree hook on the business end.
With this wire you come from the left side of the bike at the same angle as for the hump removal.
Point the hook end of the wire to the latch at the 20cm mark and wiggle it about. You clearly hear the latch rattle if you are in the correct location.
Once at that point simply push the hook around the latch and it will catch on the latch from the far side. Once it is hooked, simply pull back on the wire if you feel the spring loaded latch.
It will pop the seat up if you are hooked successfully.
Here is a photo of the hook wire that I made out of a coat hanger.
Remember to mark the wire at a point 20cm from the hook so you know how far in to poke it from the edge of the seat.
This procedure will enable access to the underside of a locked seat or hump. I would recommend not relying on that space for anything of real value and I only offer this solution as an emergency access process for owners who need to remove the hump or seat.
Simmo's pre emptive solution may be a better way for those who have the forthought to prepare for such a situation.
"If time catches up with you. You're going too slow!"
Regards BUSGO